Explore our growing library of interactive courses in math, science, data analysis, logic, languages, programming, and more.
Cold-process, hot-process, and melt-and-pour soap crafting — saponification chemistry, oil profiles, lye safety, scent blending, colorants, swirl techniques, and curing.
OthersSoy, beeswax, paraffin, coconut waxes — wick sizing, fragrance load, container vs pillar, troubleshooting tunneling and frosting, and seasonal scent blending.
OthersVegetable-tanned and chrome-tanned leathers — pattern making, saddle stitching, dyeing, edge burnishing, tooling, and making wallets, belts, and bags.
OthersHand bookbinding — Coptic stitch, Japanese stab binding, perfect binding, case binding, leather covers, headbands, and restoring antique books.
OthersCopper-foil (Tiffany) and lead-came techniques — glass cutting, foiling, soldering, patinas, panel construction, lampshades, and 3D objects.
OthersFreshwater, saltwater, and fly fishing — knots, rigs, lures, fish behavior, casting techniques, catch-and-release, and species-specific tactics.
OthersRecurve, compound, and traditional bows — stance, draw, anchor, release, arrow selection, sight tuning, and target & 3D shooting.
OthersAlpine skiing and snowboarding from beginner pizza wedge to black diamonds, parks, moguls, and powder — gear, technique, safety, and conditioning.
OthersStreet, park, and vert skating — pushing, ollies, kickflips, grinds, manuals, and dropping in on transition.
ScienceWild mushroom identification — edible vs deadly lookalikes, spore prints, habitats, seasonal calendars, and ethical foraging.
OthersStick (SMAW), MIG, TIG, and oxy-fuel welding — joint prep, settings, common weld defects, safety gear, and pipe and structural work.
OthersResidential plumbing — copper, PEX, PVC; soldering, crimping, gluing; drain & vent design; fixing leaks, replacing faucets, unclogging drains.
OthersEngine, drivetrain, brakes, suspension, and electrical systems — oil changes, brake jobs, timing belts, OBD-II diagnostics, and basic troubleshooting.
OthersRoad, mountain, and gravel bike care — tire repair, chain & drivetrain, brake & shifter tuning, wheel truing, and bottom bracket service.
OthersFix it yourself — drywall patching, wood floor repair, plumbing leaks, leaky faucets, doors, windows, and seasonal home maintenance.
ProgrammingBuild & program robots — Arduino, Raspberry Pi, motors, sensors, kinematics, computer vision, ROS, and competitive robotics challenges.
ProgrammingQuadcopters, fixed-wing, FPV racing — flight controllers, GPS waypoints, aerial photography, FAA Part 107, and DIY builds.
ProgrammingParametric and freeform CAD — Fusion 360, SolidWorks, FreeCAD basics; sketches, extrudes, lofts, assemblies, drawings, and 3D-print prep.
OthersClaymation, puppets, paper cutout, brickfilms — armatures, framerates, lip sync, sets, lighting, and frame-by-frame storytelling.
ScienceFossils, dinosaurs, deep time, evolutionary history — Cambrian explosion, mass extinctions, K-Pg boundary, hominid evolution, and field paleontology.
ScienceThe science of life beyond Earth — extremophiles, habitable zones, Europa, Enceladus, SETI, Drake equation, and the Fermi paradox.
ProgrammingBitcoin, Ethereum, blockchains — proof-of-work, proof-of-stake, smart contracts, DeFi, NFTs, wallets, and security.
OthersJapanese chanoyu, Chinese gongfu, British afternoon tea, and Moroccan mint — equipment, water, leaf selection, brewing time, and tea etiquette.
OthersFigure skating and recreational ice skating — edges, swizzles, crossovers, three-turns, spins, basic jumps, and ice etiquette.
OthersRead and use nonverbal communication — microexpressions, posture, gestures, eye contact, proxemics, and cultural differences.
OthersLong-form and short-form improv — "Yes, And," scene work, character work, the Harold, games, and finding the game of the scene.
OthersAnimation, video games, commercials, and audiobooks — voice care, accents, character voices, ADR, mic technique, and home-studio setup.
ScienceBackyard composting, vermicomposting (worms), bokashi, and large-scale — C:N ratio, hot vs cold piles, turning, troubleshooting, and applying finished compost.
ScienceDesigning self-sustaining ecosystems — Bill Mollison's 12 principles, zones, food forests, swales, water harvesting, and edible landscaping.
OthersFreshwater, saltwater, planted, and reef tanks — the nitrogen cycle, cycling a tank, fish selection, feeding, disease, and aquascaping.
OthersHand embroidery and counted cross-stitch — hoops, fabric counts, threads, basic and advanced stitches, transfer methods, and finishing techniques.
OthersPatchwork, applique, and quilting — fabric selection, rotary cutting, piecing, three-layer sandwich, hand & machine quilting, and traditional patterns.
OthersBeading, wire-wrapping, metalsmithing, and silver soldering — making earrings, necklaces, rings, and bracelets with proper findings and finishes.
OthersKnot-based fiber art — cord types, mounting, square knots, hitches, plant hangers, wall hangings, and bohemian decor.
OthersHot glass at the furnace and torch — gathering, marvering, blocking, jacks & shears, color application, and making vessels, ornaments, and beads.
OthersTile, stone, glass, and ceramic mosaics — substrates, adhesives, andamento, grouting, indoor & outdoor pieces, and Byzantine to modern styles.
OthersWave riding from whitewater foamie days to overhead reef breaks — board types, paddling, pop-up, turning, surf etiquette, and reading the ocean.
OthersIndoor gym, outdoor sport, trad, and bouldering — knots, belaying, footwork, projecting, anchors, multi-pitch, and rescue basics.
OthersFlatwater, sea, and whitewater paddling — strokes, rolls, rescues, navigation, packing for expeditions, and reading rivers.
OthersCar camping, ultralight backpacking, thru-hiking — gear, food, water, navigation, weather, Leave No Trace, and choosing a campsite.
OthersEnglish and western riding — tacking up, mounting, walk-trot-canter, jumping basics, trail riding, dressage, and horse care.
OthersOpen-water diver certification and beyond — gear, breathing, equalization, buoyancy, dive tables, marine life ID, and advanced specialties.
OthersRough & finish carpentry — measuring, framing, stairs, doors, trim, cabinet hanging, deck building, and joinery.
OthersFloors, walls, backsplashes, and shower pans — substrates, layout, cutting, thinset, grouting, waterproofing, and pattern design.
OthersHeating, ventilation, and air conditioning — refrigeration cycle, furnaces, heat pumps, ductwork, thermostats, and seasonal maintenance.
OthersPin tumbler locks, rekeying, key cutting, lock picking (legal), automotive transponder keys, safe servicing, and ethics.
ProgrammingHubs, sensors, voice assistants, automations — Home Assistant, Zigbee, Z-Wave, Matter, MQTT, energy monitoring, and privacy.
ProgrammingUnity and Unreal for Meta Quest, Vision Pro, and WebXR — XR Toolkit, hand tracking, passthrough, locomotion, comfort, and shipping to stores.
ProgrammingContainerization to production — Docker, Kubernetes pods, deployments, services, Helm, CI/CD pipelines, monitoring, and SRE practices.
ProgrammingUbuntu, Debian, RHEL, and Arch server administration — systemd, networking, firewalls, SSH hardening, package management, and shell scripting at scale.
ScienceHotspots, subduction zones, lava types, eruption styles, monitoring with seismographs and gas, and famous eruptions through history.
ScienceClimate vs weather — atmospheric circulation, ocean currents, paleoclimate, climate models, and the carbon cycle.
ScienceScientific study of fungi — taxonomy, life cycles, mycorrhizae, fermentation, medicinal mushrooms, lichens, and citizen science.
OthersRhythm tap and Broadway tap — basic steps (shuffle, flap, ball-change), time steps, syncopation, improvisation, and famous tap routines.
OthersCard tricks, coin magic, mentalism, and large-stage illusions — sleights, misdirection, presentation, scripting, and ethics of magic.
OthersBeatmatching, mixing, scratching, and producing — turntables vs CDJs vs controllers, EQing, harmonic mixing, and reading the dance floor.
OthersAncient Greek philosophy for modern life — Marcus Aurelius, Seneca, Epictetus; dichotomy of control, premeditatio malorum, journaling, and amor fati.
OthersRead faster with comprehension — eliminating subvocalization, expanding eye span, skimming and scanning, and study-mode techniques.
OthersDe-escalation, active listening, nonviolent communication, mediation, and workplace and family conflict skills.
OthersFresh egg dough, semolina, gluten development, shaping by hand and machine — tagliatelle, ravioli, gnocchi, and regional Italian shapes.
OthersButtercream, fondant, royal icing, ganache, and modeling chocolate — piping, smooth coats, drips, flowers, sculpted cakes, and wedding tiers.
OthersThe world of Care Bears — every bear, every cousin, every belly badge. Caring missions, the Care Bear Stare, Care-a-Lot geography, Cloud Cars, No-Heart, and the ethics of kindness.
ScienceWhat lies past the edge of science fiction — speculative physics, simulation theory, multiverses, time travel paradoxes, Dyson spheres, alien megastructures, and post-singularity futures.
Ten characters that speak every language we teach — hover or tap to hear their next greeting.
Bring your ideas into the real world — RepRap roots, FDM & resin (SLA, DLP, MSLA), industrial SLS / metal printers, filaments (PLA, PETG, ABS, ASA, TPU, nylon, wood), resins (tough, flexible, castable), printer anatomy, bed leveling, slicers (Cura, PrusaSlicer, Bambu Studio, OrcaSlicer), supports, infill, troubleshooting (stringing, warping), calibration (E-steps, flow, linear advance), CAD (Tinkercad, Fusion 360, OnShape, Blender), 3D scanning & photogrammetry, design for 3D printing, post-processing, multi-color, miniatures, famous printers (Prusa, Bambu, Anycubic, Voron), custom firmware (Marlin, Klipper), the Maker Movement, industry applications, bioprinting, construction printing, and the future of additive manufacturing.
Data AnalysisThe science of evidence-based decisions — the same toolkit used at Booking.com, Airbnb, Netflix, Google & Meta. Experimental design, randomization, hypothesis testing, p-values, confidence intervals, power analysis & sample size, MDE, t-tests / z-tests / chi-square / bootstrap, multiple-comparisons (Bonferroni, FDR), CUPED variance reduction, the peeking problem & sequential testing, novelty/primacy effects, SRM, multi-armed bandits & Thompson sampling, switchback & geo experiments, holdouts & long-term metrics, OEC & guardrails, network & spillover effects, Simpson's paradox, ethics, and tools (Optimizely, VWO, GrowthBook, Statsig, Eppo). Plus Bayesian A/B testing, frequentist-vs-Bayesian, ethics & Twyman's Law, reporting & storytelling, and a capstone experiment.
MathThe world's first calculator — bead by bead. History from Mesopotamian dust boards to Roman counters to the Chinese suanpan, Japanese soroban, Russian schoty, and the Cranmer abacus for blind students. Master place value, complementary number tricks (5- & 10-friend), addition & subtraction by sliding beads, multiplication & division, square & cube roots, anzan (mental abacus / blind calculation) — the technique speed-arithmetic champions use to outpace calculators — plus modern competitions (UCMAS, ALOHA Mind Math), classroom pedagogy, the cognitive-development research, and abacus apps.
OthersMeet the creator of Mathagram — his journey, art on DeviantArt (with a dedicated unit on the public portfolio and Mathagram mascots), Rehaan's own character reference sheet (the blue-heart eyebrow, color palette, proportions, and how the design connects to the Lighthouse logo), the story behind the platform, and his vision for the future.
OthersFrom audition to opening night — every technique deep (Stanislavski, Meisner, Strasberg, Adler, Hagen, Suzuki & Viewpoints, Alexander, Linklater, Knight-Thompson), stage combat, movement & dance, audition/self-tape/cold reading, improv (long & short), stand-up, sketch & solo, voiceover, audiobook narration, dialects, mime & mask, Commedia dell'arte, full theater history (Greek/Roman, Medieval, Shakespeare, Restoration, Realists, Brecht, Beckett, Williams/Miller/O'Neill, August Wilson), musical theater (Sondheim, Hamilton), production crew, Broadway, film & TV career, agents, and the great performers.
OthersThe most comprehensive afterlife course — every world religion, mythology, and philosophy on death. Heavens and hells with their specific levels (Dante's 9 spheres & circles, Islamic Jannah & Jahannam, Hindu lokas & narakas, Buddhist deva realms & hot/cold hells, Norse Helheim, Egyptian Duat). Tibetan & Egyptian Books of the Dead. NDE and reincarnation research. Mummification, cremation, burials, mausoleums. Spiritualism, mediumship, Theosophy. Modern hospice & green burial. Afterlife in literature & pop culture. Ghosts, animals, and digital afterlife.
LanguageThe Australian Institute of Aboriginal and Torres Strait Islander Studies' Duolingo-partnership approach to language revitalisation — Yolŋu Matha, Pitjantjatjara, Warlpiri, Arrernte, Wiradjuri, Gamilaraay, Noongar, Yawuru, Bundjalung, Kaurna, Torres Strait languages (Yumplatok, Meriam Mir, Kala Lagaw Ya), palawa kani reawakening, Murrinh-Patha, Tiwi, Anindilyakwa, Pilbara languages, songlines, kinship, place names, bush foods, art, music, famous Indigenous Australians, and reconciliation/treaty.
LanguageSpeak Shqip — the Albanian language, an Indo-European isolate spoken in Albania, Kosovo, North Macedonia, Montenegro and a global diaspora. The 36-letter alphabet, definite-suffix grammar,…
OthersThe life, ideas, and legacy of Albert Einstein — from Ulm and the patent office to relativity, quantum debates, Princeton, and humanitarian advocacy.
MathThe ultimate algebra course — foundations, functions, polynomials, linear algebra, trigonometry, modeling, data, competitions, SAT/ACT prep, and history.
Programming & CSThink like a computer scientist — data structures, sorting, searching, graphs, dynamic programming, network flow, advanced trees, computational geometry, randomized algorithms, NP-completeness, and the classic algorithms every coder should know.
LanguageThe greatest constructed alien tongues — Klingon, Vulcan, Romulan, Bajoran, Cardassian, Ferengi, Sith, Huttese, Jawa, Wookiee, Aurebesh, Gallifreyan, Dalek, Minbari, Cylon, Mass Effect races, Halo Covenant, Destiny races, Asgardian, Kryptonian, Cybertronian, Yautja, Xenomorph, Heptapod B, Na'vi — plus speculative biology, whale song & dolphin codas, SETI/METI, Lincos, the Voyager Golden Record, and a full conlang studio.
LanguageThe official language of Ethiopia — Ge'ez script, grammar, coffee culture, history, and Amharic mastery.
ScienceHow the human body works — every system from skeletal to nervous to endocrine, organs, tissues, homeostasis, common diseases, clinical applications, the tongue & the 5 basic tastes (sweet, sour, salty, bitter, umami — plus the trigeminal "spicy" myth), and how muscle works for working out (fiber types, hypertrophy, progressive overload, DOMS).
ScienceThe animal kingdom and plant world — wildlife of every continent, ocean depths, island ecosystems, rainforest layers, and extreme survival. Classification, anatomy, photosynthesis, behavior, evolution, fungi, lichens, algae, ecosystems, and conservation.
MathCollect, analyze, and draw conclusions from data. AP exam prep, advanced inference, regression, data science, financial math, and workplace statistics.
ScienceThe science of digging up the human past — site survey, stratigraphy & the Harris matrix, excavation, dating (C-14, dendrochronology, OSL), pottery, lithics, metallurgy, zoo- & archaeo-botany, bioarchaeology & ancient DNA, the Paleolithic to Iron Age, Egypt, Mesopotamia, Indus, China & the Terracotta Army, Greece & Rome (Pompeii), Maya, Aztec, Inca, Cahokia, Great Zimbabwe, Polynesian voyaging, underwater & industrial archaeology, forensic archaeology, famous finds (Tutankhamun, Rosetta Stone, Dead Sea Scrolls, Ötzi), looting & repatriation, museums, and AI/LiDAR's future.
LanguageAn ancient Indo-European language with its own script since 405 AD. 10 units, 200 lessons.
OthersDrawing, painting, digital art, character design, anatomy, comics, manga, animation, pixel art, 3D, photography, DeviantArt, art history, and falconry — the ancient art of training raptors.
Programming & CSUnderstand AI and ML — neural networks, deep learning, NLP, computer vision, transformers, LLMs, generative AI, and ethics.
OthersBirth charts, zodiac signs, planets, houses, aspects, transits, synastry, and Western vs Vedic astrology.
ScienceThe entire universe and beyond — Kepler systems, nebulae, galaxy clusters, cosmic web, astrobiology, space missions, multiverse, megaverse, omniverse, and the cosmos.
LanguageThe mother of all human tongues — Marc Okrand's constructed language for Disney's Atlantis: The Lost Empire. Phonology, the boustrophedon script, all of grammar, royal vs common registers, the Royal Family (Kashekim, Kida), the Heart of Atlantis & crystal lore, Aktirak vehicles, Atlantean architecture, mythology & the Leviathan, the Shepherd's Journal, poetry & songs, and side-by-side with Marc Okrand's other conlang Klingon.
ScienceThe science of flight — the four forces, airfoils, control surfaces, piston / turboprop / turbofan / jet engines, the atmosphere & density altitude, aviation weather, METARs & TAFs, the cockpit "six pack", glass avionics, navigation (pilotage, VOR, ILS, GPS), charts, airspace classes, air traffic control, radio phraseology, airports, takeoff/landing performance, stalls & spins, FAA/ICAO regulations, pilot certificates, IFR, aviation history (Wright Brothers, Lindbergh, WWII, Jet Age, Concorde), Boeing vs Airbus, famous aircraft (DC-3, 747, SR-71), helicopters, gliders, drones, bush flying, safety & famous accidents, the future (eVTOL, SAF, hypersonic), plus aircraft structures & materials, hydraulic / pneumatic / electrical systems, CRM & aeronautical decision-making, general aviation life, mission aviation (SAR, MedEvac, firefighting, crop dusting), flight simulation, and great aviators (Yeager, Tuskegee Airmen, Bessie Coleman, Sully Sullenberger).
LanguageA Turkic language spoken by 30 million people in Azerbaijan and Iran. Mugham music, Caspian heritage, Nizami & Fuzuli poetry, carpets & crafts, and the Iranian Azerbaijani diaspora.
OthersExplore the infinite labyrinth — every level, entity, object, and survival strategy. From Level 0 to the Frontrooms.
LanguageEurope's only surviving language isolate — no known relatives anywhere on Earth. Spoken by ~1 million in the Basque Country (Euskal Herria) across northern Spain and southwestern France. Pre-dates the Indo-European invasion. Ergative-absolutive grammar, vigesimal counting, agglutinative morphology, and a 4,000-year-old cultural legacy. Not taught by Duolingo.
OthersSmokers, wood selection, brisket, ribs, pulled pork, regional BBQ traditions (Texas, Carolinas, KC, Memphis), competition prep.
ScienceBee biology, hive equipment, seasonal management, honey harvest, pests, queen rearing, pollination services, and selling.
OthersHome brewing — malt, hops, yeast, water; mashing, fermentation, every beer style (IPA, stout, lager, sour), bottling, recipe design.
LanguageThe language of Bangladesh and West Bengal — spoken by 230+ million people. Beautiful Bangla script and Rabindranath Tagore.
MathHyperoperations, Knuth arrows, Graham's number, TREE(3), SCG(13), Busy Beaver, Rayo number, and numbers so large they break notation itself.
MathGo far beyond circles and squares — non-Euclidean geometry, topology, Möbius strips, Klein bottles, fractals, Mandelbrot sets, higher-dimensional polytopes, knot theory, tessellations, minimal surfaces, impossible objects, oblate spheroids and quadrics, prisms, pyramids, cones, cylinders, ruled and developable surfaces, higher-genus surfaces, polyhedron compounds and stellations, Catalan solids, space-filling honeycombs, Goldberg polyhedra, superquadrics, and exotic plane curves.
Data AnalysisDistributed processing at scale — the 5 Vs of Big Data, MapReduce origins (Google paper), Hadoop & HDFS, YARN, the Hadoop ecosystem (Hive, Pig, HBase), Apache Spark (RDDs, DataFrames, Datasets, SQL, Catalyst optimizer), Spark Structured Streaming, Spark MLlib, Delta Lake, Apache Iceberg & Hudi, Apache Kafka (topics, partitions, consumer groups, Kafka Connect, Kafka Streams, ksqlDB), Schema Registry & Avro/Protobuf, Apache Flink, Apache Beam, the lakehouse, Parquet & ORC, partitioning & bucketing, AQE, cluster autoscaling, Databricks, Snowflake, BigQuery, and a full big-data capstone.
ScienceThe science of life — cells, DNA, evolution, genetics, anatomy, plants, animals, fungi & microbes, ecology, biodiversity, immune system, reproduction, animal behavior, genomics, biotechnology, CRISPR, stem cells, synthetic biology, neurobiology, endocrinology, pharmacology, virology, vaccinology, marine & freshwater biology, conservation genetics, astrobiology, paleobiology, aging, sleep, behavioral ecology, animal cognition, bioethics, and forensic biology.
OthersFrom your backyard feeder to a Big Year — bird anatomy, field marks & GISS, birding by ear, binoculars & scopes, Sibley & Peterson guides, raptors, owls, waterfowl, shorebirds, seabirds, wading birds, hummingbirds, woodpeckers, corvids, parrots, penguins, migration mysteries, courtship & nesting, bird photography, hawkwatching, eBird citizen science, Roger Tory Peterson, the Cornell Lab, extinct birds (Dodo, Passenger Pigeon), conservation success stories, world hotspots (Costa Rica, Ecuador, India), and the birders' code.
Programming & CSMaster Blender — free 3D creation suite. Modeling, sculpting, texturing, animation, rendering, VFX, geometry nodes, and video editing. 375 lessons across 25 units.
OthersMaster classic and modern board games — Checkers, Backgammon, Go, Mancala, Shogi, Othello, Scrabble, plus Catan, Ticket to Ride, Carcassonne, Pandemic, Dominion, 7 Wonders, Wingspan, Terraforming Mars, Scythe, Gloomhaven, Twilight Imperium, Risk, Diplomacy; deckbuilding, worker placement, area control, engine-building, roll-and-write, hidden role, party, trivia, family, wargames, MTG, Bridge, Poker, Solitaire, famous designers (Knizia, Rosenberg, Feld, Vlaada Chvátil), BGG culture, conventions, awards, and tournament play. No chess.
OthersWater sorting, door & key puzzles, mazes, escape rooms, trick questions, IQ tests, fill-all-squares paths, Wordscapes-style letter dragging with 6- & 7-letter power words, and optical illusions — just like mobile brain games.
OthersFrom basic loaves to sourdough mastery — flour, hydration, kneading, fermentation, sourdough starters, shaping, scoring, enriched doughs.
LanguageLearn Burmese — the official language of Myanmar, written in beautiful circular script. 174 lessons across 12 units.
MathMaster limits, derivatives, integrals, sequences, series, multivariable calculus, vector calculus (line/surface integrals, Green's/Stokes'/Divergence), complex analysis, tensors, ML, physics, economics, biology, AP prep, competitions, and lesson quizzes. Standalone vector basics now live in the dedicated Vectors course.
OthersThe art of beautiful writing across the world — Italic, Copperplate, Spencerian, Blackletter, Uncial, Carolingian, Humanist, Foundational, Fraktur, Rotunda, Textura, Bâtarde, Chinese (5 styles), Japanese Shodō, Korean Hangul, Arabic (7 styles), Hebrew STAM, Devanagari, Tibetan, Cyrillic Vyaz, Greek — plus pen anatomy, inks, papers, digital calligraphy, branding hand-lettering, wedding stationery, sign painting, tattoo lettering, and illumination.
LanguageMaster Catalan — grammar, all dialects (Valencian, Balearic, Northern, Alguerès), folklore, literature, cooking, and professional fluency.
LanguageEvery character a keyboard can produce — ASCII & Unicode, Latin diacritics, Cyrillic, Greek, IPA, math & currency, punctuation, arrows, CJK ideographs, Hangul, Arabic, Hebrew, Devanagari, emoji, ligatures, old scripts, Braille, Morse, NATO phonetic; Vietnamese / Polish / Hungarian / Turkish / Esperanto special letters; Romanization & Pinyin tones; Roman numerals, fractions, letterlike math; card & chess suits, music notation, zodiac & planetary; dingbats & Wingdings, whitespace & zero-width chars; emoji modifiers & flags; Unicode normalization, homoglyph spoofing, Punycode, HTML entities, kaomoji, ASCII art; Thai / Lao / Khmer / Burmese / Tibetan / Mongolian; all South & other Indic scripts; African scripts (Ge'ez, Tifinagh, Adlam, N'Ko); Indigenous syllabics; Coptic / Gothic / Glagolitic; CJK traditional vs simplified; Hangul Jamo; furigana & vertical writing; ANSI terminal escapes; regex classes — and how to type them all.
ScienceMaster atomic structure, bonding, reactions, kinetics, thermodynamics, equilibrium, electrochemistry; organic deep (alkanes, alkenes, aromatics, stereochemistry, SN/E mechanisms, EAS, carbonyls, aldol, Wittig, Diels-Alder, radicals, organometallics, asymmetric synthesis, total synthesis, polymers); spectroscopy (NMR, IR, UV-Vis, MS, chromatography); inorganic (transition metals, lanthanides, coordination, crystal field); physical chemistry (quantum, statistical thermo, surface, colloid, photochemistry, catalysis, computational); biochemistry deep (glycolysis, Krebs, ETC, β-oxidation, AA metabolism, PPP, photosynthesis, vitamins, hormones, enzyme kinetics); turbulent fluid (Reynolds number, mixing in reactors & bioreactors, Kolmogorov scales, blood-flow turbulence); pharmaceutical, environmental, industrial, nuclear, lab techniques, forensics, famous chemists, and AP exam prep.
ScienceBuild and analyze electrical circuits — Ohm's law to op-amps, PCB design, IoT, motors, electric vehicles, RF, and renewable energy.
ScienceThe deep dive on pre-relativistic, pre-quantum mechanics — kinematics, Newton's laws, energy & momentum, rotation & angular momentum, rigid bodies, gravitation & orbits, oscillations & normal modes, the Lagrangian & Hamiltonian formulations, central forces, non-inertial frames, and continuum & fluid mechanics.
OthersMicrosoft 365, Google Workspace, Apple iWork & iCloud, plus Notion, Airtable, Slack, Asana, Trello, Zoom, Dropbox — and the collaboration, versioning, security, and workflow habits that make them work together.
Data AnalysisK-Means, DBSCAN, decision trees, random forests, SVM, neural networks, PCA, model evaluation, and lesson quizzes for every major ML topic.
OthersBar tools, every spirit, classic cocktails (Old Fashioned, Manhattan, Martini), tiki, sours, highballs, modern molecular mixology.
OthersOne combined deep course on the world's two greatest brewed drinks — coffee from bean origins through espresso & latte art, plus every major tea tradition (Japanese chanoyu, Chinese gongfu, British afternoon, Indian chai, Russian samovar, Moroccan mint, yerba mate). Long units (25 lessons each) for full depth.
ScienceThe math, science, history, and culture of color — every color deep-dive (red/blue/yellow/green/purple/orange/pink/brown/white/black/metallics), color math & spaces (RGB, CMYK, LAB, OKLAB, blending modes), color theory, impossible colors, Vantablack, YInMn, structural color, vision & tetrachromacy, synthetic-dye revolution (Mauveine), color in art history (cave paintings → Renaissance → Impressionism → Bauhaus → modernism → post-war), Albers & Itten theory, cinema color & grading, photography history, ICC management, HDR, branding psychology, color across cultures (Chinese, Indian, Japanese, Tibetan, African), religion & symbolism, flags & heraldry, cartography (ColorBrewer, viridis), and WCAG accessibility.
Programming & CSCode in Minecraft with command blocks — coordinates, selectors, /execute, scoreboards, NBT, datapacks, redstone (a dedicated intro unit on dust, torches, repeaters, comparators, pistons, observers, logic gates & clocks), and full mini-game maps.
Programming & CSHow computers work — binary, logic gates, CPU, memory, operating systems, networking, cryptography, and computational thinking.
OthersLearn to cook and eat well — knife skills, every technique (sauté, braise, roast, sous vide, smoke), mother sauces, stocks, breads, sourdough, pasta, rice, butchery, seafood, charcuterie, fermentation, pastry, ice cream, regional US, Japanese, Chinese, Indian, Mediterranean, Latin American, Middle Eastern, Southeast Asian cuisines, and a deep dive into baking — cookies, cheesecakes, choux, macarons, world pastry, holiday baking, wedding cakes, sugar work, and pastry chemistry.
OthersCosplay from concept to convention — character choice, foam & Worbla, sewing, armor, prop building, wig styling, makeup, posing.
Programming & CSMaster C++ from scratch — pointers, references, RAII, OOP, templates, STL, smart pointers, move semantics, modern C++20/23, and real projects.
OthersTell stories that matter — fiction, poetry, screenwriting, worldbuilding, characters, dialogue, sentence craft, show don't tell, point of view, voice, imagery, figurative language, subtext, symbolism, magical realism, hard SF, fantasy subgenres, horror, mystery, romance, memoir, travel & food writing, longform journalism, flash fiction, and workshop critique.
LogicCollege-level capstone — formal logic, argument analysis, statistical and scientific reasoning, decision analysis, ethics, and worksheet-driven case studies.
LogicCodes, ciphers, encryption, hashing, digital signatures, and the math & logic behind modern cryptography.
Programming & CSDefend digital systems — threats, encryption, network security, ethical hacking, penetration testing, forensics, and security operations.
OthersPractice rhythm-arrow games on your computer keyboard — playable arena (press ← ↓ ↑ → in time with falling arrows, 4 difficulty tiers from 60 to 200 BPM) plus structured drills at every BPM, FNF Week 1–7 chart walkthroughs, DDR doubles, Pump It Up, jacks, trills, streams, stamina charts, sight-reading, and speedrunning.
OthersMove to the music — ballet, jazz, tap, modern, hip-hop, latin, ballroom, cultural folk, and a Just Dance camera lesson that scores your moves. Featuring Steve the Fox, your dance mascot.
Data AnalysisTurn data into insight — chart selection (bar, line, scatter, pie, treemap, sankey, heatmap, violin, network, sparkline), Tableau / Power BI / Looker Studio / Qlik / Apache Superset / Metabase / Grafana / Kibana / QuickSight / ThoughtSpot / Sigma, programmatic viz (D3, Vega/Vega-Lite, Plotly/Dash, Streamlit, Bokeh, Observable), mapping (Leaflet, Mapbox, Deck.gl), web & product analytics (GA4, Mixpanel, Amplitude), SaaS metrics (MRR/ARR/churn/LTV/CAC), sales & marketing dashboards, famous data viz designers (Tufte, Cairo, Knaflic, Wilke), and a 21-lesson capstone.
Data AnalysisBuild the pipelines that feed the analysts — the data-engineering lifecycle, batch vs streaming, ETL vs ELT, the modern data stack (Fivetran, Airbyte, dbt, Snowflake), orchestration (Airflow, Dagster, Prefect), idempotency & retries, dbt fundamentals (models, sources, tests, snapshots, macros), star schema, SCDs, Kimball vs Inmon, lakehouse, file formats (Parquet, Avro, ORC, Delta, Iceberg, Hudi), CDC (Debezium), Kafka pipelines, data quality (Great Expectations, Monte Carlo, Soda), data contracts, lineage (OpenLineage, DataHub), catalogs (Atlan, Unity Catalog), governance & PII, real-time pipelines (Flink, Materialize), cloud platforms (AWS, GCP, Azure), SLAs & on-call for data, message queues (SQS, RabbitMQ, Pub/Sub), serverless data (Athena, BigQuery, Snowpark), Spark & PySpark, and a capstone end-to-end pipeline.
Data AnalysisUse data responsibly — privacy laws (GDPR, CCPA, HIPAA, China PIPL, India DPDP, Brazil LGPD), cross-border transfers (Schrems II, SCCs, BCRs), Privacy by Design, dark patterns, cookie banners, DSARs & data subject rights, federated learning, synthetic data, homomorphic encryption & SMPC, AI safety & alignment, LLM training-data ethics, industry-specific (healthcare, education, finance, employment, advertising), IoT/wearables/connected-vehicle privacy, plus a 21-lesson capstone on building a privacy-respecting product.
Programming & CSMaster data structures — arrays, linked lists, stacks, queues, trees, heaps, hash tables, graphs, tries, with Big-O and interview problems.
Data AnalysisData Cleaning, Manipulation, Preprocessing for ML — CSV, JSON, SQL, Python, pipelines, and real-world projects.
LogicRational choice, expected utility, risk, Bayesian reasoning, behavioral economics, and multi-criteria decisions. Plus cognitive biases, intertemporal choice, crisis decisions, negotiation, public policy, medicine, law, military, finance, sports, the Bayesian brain, history of decision theory, cross-cultural & evolutionary decisions, and hands-on workshops.
MathMaster the math, history, and applications of dice — from ancient astragali to casino-grade precision. Single & multi-dice probability, expected value, variance, Bayes, distributions (uniform, binomial, normal via CLT), Monte Carlo simulation, random walks & Markov chains, board games (Backgammon, Monopoly, Risk, Catan), tabletop RPGs (D&D 5e, Pathfinder, Call of Cthulhu — notation, criticals, saves), casino games (Craps, Sic Bo, Liar's Dice, Yahtzee, house edge), cheating detection, non-transitive dice & Penney's game, De Méré & birthday paradoxes, Diceware cryptography, magic tricks, capstone. Plus video-game RNG & loot tables, streaming dice culture, polyhedral geometry, combinatorics, statistics history (Pascal/Fermat/Pearson/Fisher), quantum dice & philosophy, and dice across cultures.
ScienceMaster the most complex molecules in chemistry — from buckminsterfullerene to DNA, pharmaceuticals to molecular machines, and gemstone minerals like beryl (beryllium aluminium cyclosilicate). No simple molecules here.
Programming & CSExplore logic gates, binary arithmetic, sequential logic, FSMs, memory, FPGAs, HDLs, and CPU architecture. 379 lessons across 29 units.
OthersTrain any dog at any age — puppy basics, house training, leash walking, sit/stay/come, recall, socialization, behavior modification, separation anxiety, aggression, clicker training, positive reinforcement, breed-specific tips, agility, service dog work, and famous trainers.
LanguageThe language of the Dothraki horselords from Game of Thrones — David J. Peterson's creation. Grammar, vocabulary, khaleesi speeches, songs & oral tradition, Vaes Dothrak, the Dothraki Sea geography, anatomy, colors, time, animals & plants of Essos, marketplace conversation, and cultural mastery.
OthersTrain your eye and hand — line, value, perspective, anatomy, gesture, portraits, landscapes, and urban sketching with pencil, charcoal, ink.
LanguageThe Elvish languages of Middle-earth — Quenya and Sindarin by J.R.R. Tolkien. Tengwar script, Cirth runes, full Eldarin family tree (Vanyarin, Noldorin, Telerin, Nandorin, Avarin, Silvan), advanced verb systems, Sindarin mutations, vocabulary deep dives, Lay of Beren, Galadriel's Phial, every major character & place name, and reading Tengwar inscriptions.
LanguageGrammar, 2000+ OED words with IPA — medical, psychology, art, music, culinary, architecture, nature, war, nautical, astronomy, and math vocabulary.
LanguageTrace the evolution of English — from Old English runes to global digital English. Literature, grammar, dialects, and the people who shaped our language.
OthersStart and grow a business — ideas, planning, marketing, finance, leadership, branding, and scaling from side project to startup.
LanguageZamenhof's international auxiliary language — fully regular grammar, 16 rules, every life-domain vocabulary set, idioms & proverbs, country-by-country communities, Pasporta Servo, the Universal Congress, Esperanto online (Lernu, Vikipedio, Duolingo), comparisons with Volapük / Ido / Interlingua / Lojban / Toki Pona, history of suppression & survival, native-speaker families, AI-era machine translation, and certification paths.
OthersModern etiquette — dining, business, weddings, funerals, email, royal & formal, cultural differences, kids manners.
Data AnalysisTurn raw numbers into compelling visual stories — bar charts, scatter plots, heatmaps, dashboards, and storytelling with data.
OthersHow factories work — assembly lines, automation, robotics, quality control, repair & servicing, packaging, warehousing, lean manufacturing, Six Sigma, 3D printing, CNC, welding, casting, semiconductor fabs, pharma, aerospace, shipbuilding, EV gigafactories, paper & pulp, chemicals, newspaper presses, supply chains, labor history, and industrial disasters.
OthersSauerkraut, kimchi, kombucha, yogurt, kefir, pickles, hot sauces, sourdough — every major fermentation tradition.
LanguageSurvey of fictional tongues with Duolingo-style character speakers — James (Klingon, Mando'a), Rita (High Valyrian, royal court), Steve (Dothraki, insults), Gosia (Sindarin, Quenya, Tengwar), Diego (Na'vi, Vulcan, conlang theory), William (Huttese, toasts), Sam (Aurebesh, numbers), Edam (greetings & guide). Plus famous conlang inventors and how to build your own.
LanguageThe national language of the Philippines — verb focus system, Taglish, OFW culture, adobo, fiestas, and 7,641 islands.
OthersFrom an idea on a napkin to a finished film — three-act structure & the Hero's Journey, screenwriting, character & dialogue, pre-production, cameras & lenses, composition & shot types, camera movement, three-point lighting, color & mood, sound design, boom mics, editing (Premiere, Final Cut, DaVinci, Avid), color grading, VFX & greenscreen, practical effects, famous directors (Hitchcock, Kubrick, Spielberg, Tarantino, Scorsese, Kurosawa, Miyazaki, Bong Joon-ho), animation (Pixar, Ghibli, stop-motion), genre deep-dives (western, noir, musical, doc), film festivals (Sundance, Cannes, Berlin), the streaming era, and virtual production / AI in film.
OthersBudgeting, investing, crypto, taxes, FIRE, side hustles, stock market, real estate, financial math, goods & services, and economic history.
OthersReal life-saving skills — adult/pediatric/infant CPR, AEDs, choking (adult & infant), severe bleeding & tourniquets, advanced wound care, burns, fractures & splinting, spinal injury, head injury & concussion, eye injury, heart attack, stroke (FAST/BE-FAST), anaphylaxis & EpiPens, asthma, diabetic emergencies, seizures, hypothermia, heat emergencies, drowning, poisoning, naloxone (Narcan), mental health first aid, suicide crisis response, and disaster first aid — plus a capstone.
ScienceThe science of solving crime — Locard's principle, crime scene investigation, fingerprint & DNA analysis, bloodstain pattern analysis, ballistics, trace evidence, toxicology, document examination, forensic anthropology / odontology / entomology, autopsy, criminal profiling (FBI BAU), digital forensics, courtroom testimony, the chain-of-custody, famous cases (O.J. Simpson, JonBenét Ramsey, Golden State Killer, BTK), the Innocence Project, wrongful convictions, bias, ethics, careers, and the future (rapid DNA, AI in forensics, forensic genealogy).
LogicPropositional logic, predicate logic, truth tables, proofs, modal logic, and metalogic.
LanguageLa langue de l'amour, diplomatie & culture. Spoken by 320+ million across France, Belgium, Switzerland, Canada (Québec), and 29 African countries (DR Congo, Côte d'Ivoire, Senegal). Nasal vowels, liaison, gendered nouns, complex verb conjugations, & the literary heritage of Hugo, Voltaire, Camus, Proust. From bonjour to fluency.
LanguageThe closest living relative of English — sailing, Wadden Sea, Old Frisian, islands, agriculture, and North/Sater Frisian.
Programming & CSMake games end-to-end — Unity, Unreal, Godot, C#, GDScript, game design, level design, sprite animation, 3D modeling, physics, AI, networking, sound, and shipping to Steam & consoles.
LogicStrategic thinking — Prisoner's Dilemma, auctions, evolutionary games, mechanism design, and voting theory.
ScienceFrom seed to harvest — soil science, hand tools, vegetable beds, herb gardens, flower beds, fruit trees, lawn care, pruning, composting, pest management, watering systems, container gardening, seasonal planning, hydroponics, native landscaping, pollinator gardens, and growing food year-round.
ScienceDNA, genes, and inheritance — Mendel's laws, Punnett squares, mutations, replication, transcription, translation, gene regulation, genetic diseases, CRISPR, gene editing, population genetics, epigenetics, and genome sequencing.
ScienceCountries, capitals, continents, oceans, climate zones, and the physical and human geography of Earth.
ScienceHow Earth works — Earth's layers, plate tectonics, rocks & minerals, crystallography, gemstones, igneous/sedimentary/metamorphic petrology, stratigraphy, volcanoes, earthquakes, tsunamis, mountains, rivers, glaciers, deserts, caves & karst, coral reefs, fossils, geological time, mass extinctions, Mesozoic & Cenozoic, hydrogeology, coastal geology, geomorphology, ore deposits, petroleum & coal, geothermal energy, engineering & environmental geology, geophysics, and planetary geology of Mars, Moon, and asteroids.
OthersPower, geography, and the global order — the Westphalian state system, hard / soft / sharp power, Mackinder's Heartland, Spykman's Rimland, Mahan & Sea Power, realism vs liberalism vs constructivism, polarity, the Cold War & containment, US hegemony, China & the Belt and Road, Russia, the EU, India, Japan & the Indo-Pacific, the Middle East, Iran, Saudi Arabia, Turkey, the Korean Peninsula, Taiwan & the South China Sea, Africa, Latin America, the Arctic, energy & water geopolitics, food security, maritime chokepoints (Hormuz, Malacca, Suez), cyber warfare, space geopolitics, climate geopolitics, migration as strategy, US–China competition, and the future order.
LanguageA Kartvelian language with its own unique alphabet. 33 units and 435 lessons — from basics to certification.
Data AnalysisMaps as data — lat/lon, coordinate reference systems (CRS, EPSG, WGS84, Web Mercator), projections, vector formats (GeoJSON, Shapefile, GeoPackage), raster formats (GeoTIFF, COG, NetCDF), QGIS & ArcGIS, Python ecosystem (Geopandas, Shapely, Rasterio, Folium, Pydeck, Kepler.gl), R sf & terra, spatial operations (intersect, within, buffer, joins), distance & geodesics, geocoding, isochrones & routing (OSRM, Valhalla), choropleths, heat maps & KDE, spatial autocorrelation (Moran's I), hot-spot analysis, GWR, spatial clustering (DBSCAN), interpolation (IDW, Kriging), satellite imagery (Sentinel, Landsat, Google Earth Engine), OpenStreetMap, web mapping (Leaflet, Mapbox, MapLibre, deck.gl), PostGIS & BigQuery GIS, and a real-world map capstone.
Programming & CSMaster Git — commits, branches, merging, rebasing, remotes, pull requests, conflict resolution, workflows, GitHub, and team collaboration.
OthersZalgo text, box-drawing, Unicode exploits, ASCII art, kaomoji, cursed text, Braille art, ancient scripts, and glitch aesthetics.
LanguageThe tongue of the System Lords from Stargate — Egyptian-derived phonology, hieroglyphic script, Jaffa & Tok'ra dialects, command phrases, and System Lord mythology.
MathThe mathematics of symmetry — from basic groups to Galois theory and modern abstract algebra.
OthersThe hardest thing on Mathagram. 180 brutal cross-subject questions — Putnam-tier calculus, abstract algebra, IMO geometry, Riemann-adjacent number theory, extremal combinatorics, hardest competitive programming, NP-hard algorithms, knights-and-knaves logic, dead-language translation, memory marathon (Pi to 1000), speed trial, and a no-help no-skip FINAL BOSS that pulls from every course. Beat this and you've truly mastered the site.
LanguageThe language of Gandhi — Devanagari script, grammar, Garba, Navratri, Kathiawadi & Surati dialects.
OthersMedicinal herbs deep — tinctures, salves, teas, foraging, pharmacology, apothecary, pregnancy & children safety, full materia medica reference, plus expanded coverage of culinary & aromatic herbs (cinnamon, clove, saffron, vanilla), Artemisia family (mugwort, wormwood, sweet annie), nervines (vervain, motherwort, hops), adaptogens (ashwagandha, rhodiola, schisandra, eleuthero, astragalus), medicinal mushrooms (reishi, cordyceps, lion's mane, chaga, turkey tail, maitake, shiitake), Ayurvedic herbs (gotu kola, bacopa), and a modern herbal practice capstone.
ScienceCricut, Silhouette, 3D printers, laser cutters, CNC, sublimation, laminating, vinyl, screen printing, embroidery, and resin.
OthersThe full picture — from print & broadcast history to AIDA, targeting, copywriting, creative direction, every channel (TV, radio, print, OOH, digital), programmatic real-time bidding, search/SEO/SEM, social ads (Meta, TikTok, X, LinkedIn), influencer & native, cookies & tracking, GDPR/CCPA/ATT privacy, attribution, persuasion psychology, and famous campaigns.
Programming & CSBits, bytes, files, and drives — understand digital storage from a single bit to exabyte-scale data centers. 225 lessons across 15 units.
LanguageThe galactic trade tongue of Tatooine, Jabba's Palace, and the Star Wars underworld — Ben Burtt's Quechua-inspired creation. Greetings, bargaining, smuggler slang, pod racing, Hutt cartel politics, every famous quote (Han, Greedo, Watto, Jabba, Boba Fett), and the culture of Mos Eisley.
OthersHypnosis history & science, every induction (eye-fixation, Elman, rapid, confusion, progressive), suggestion & imagery, self-hypnosis, Ericksonian indirect suggestion, NLP & conversational/covert hypnosis, hypnotizability scales, anchoring, post-hypnotic suggestion, age regression, parts therapy, hypnoanesthesia & hypnobirthing, sports/sleep/phobia/confidence applications, the brain in trance, forensic hypnosis, stage hypnosis & mentalism, cultural trance, ethics, and building a practice.
LanguageThe Viking language — four cases, sagas, Eddas, Björk, volcanoes, glaciers, Northern Lights, puffins, hot springs, and elves.
LanguageA major language of southeastern Nigeria — spoken by 45+ million people. Tonal language with rich oral tradition and Nsibidi symbols.
MathBaldi-style math! Edam starts nice, then gets FURIOUS as questions get impossible. How far can you survive?
LanguageLearn Bahasa Indonesia — simple grammar, affixes, vocabulary, conversation, culture, and regional diversity.
LogicThe mathematics of communication — Shannon's 1948 foundation through modern capacity-approaching codes. Bits & surprise, entropy (joint, conditional, cross, KL), mutual information, source coding (Huffman, arithmetic, Lempel-Ziv, DEFLATE, BWT, Brotli, Zstandard), lossy & perceptual coding (JPEG, MP3, AAC, Opus, H.264, AV1), Kolmogorov complexity, noisy channels & the Shannon-Hartley capacity theorem, error detection (CRC) & correction (Hamming, Reed-Solomon, BCH, Golay, convolutional + Viterbi, turbo, LDPC, polar), rate-distortion, quantum information, and applications from Voyager to 5G to deep learning's cross-entropy loss.
MusicLearn to play musical instruments — classical & jazz piano, fingerstyle & lead guitar, slap bass, jazz drums, violin bowing & vibrato, brass range building, woodwind embouchure, altissimo sax, banjo rolls, harp pedals, Hammond B3, synth & modular, theremin, and world instruments from India, Japan, Africa, Latin America, and the Middle East.
LanguageMaster International Sign — the contact sign language used at international Deaf events, conferences, and travel. Covers ASL, BSL, JSL, and more.
OthersLand your dream internship — resumes, cover letters, interviews, networking, and workplace skills.
LanguageTranscribe any language — consonants, vowels, tones, diacritics, acoustic phonetics, speech therapy, singing, and 50+ languages.
Others❓ Every question word in English — 5 W’s & H, yes/no, tag, choice, indirect, polite, negative, rhetorical, whom · whose · which · that, archaic wherein/whereof/whither/whence, the -soever suffix, cleft Q, free relatives, echo Q, declarative Q, multiple-wh, world question marks (¿ ; ՞ ؟), 20 languages, Socratic pedagogy, hypothetical, and conversational repair.
Programming & CSLearn Java end-to-end — JVM basics, OOP, collections, generics, streams, lambdas, concurrency, JDBC, Spring Boot, testing, and real projects.
Programming & CSMaster JavaScript — variables, async, promises, ES2024, the DOM, modules, fetch, classes, Node.js, testing, bundlers, and real projects.
LanguageLearn Kazakh — a Turkic language spoken by 13 million people in Kazakhstan. Nomadic heritage and steppe culture.
MusicComputer keyboards end-to-end — history (typewriters → IBM Model M → modern customs), layouts (QWERTY family + Dvorak/Colemak/Workman), mechanical switches, switch manufacturers, frankenswitches, spring swaps, stem materials, plate & case materials, 3D-printed & hand-wired boards, QMK/VIA/ZMK/KMK firmware, custom cables, maintenance & vintage restoration, famous customs (Norbauer, Keycult, Hibi), Keychron, Wooting Hall-Effect, NuPhy low-profile, group buys, artisans, photography, streaming, ergonomics, touch-typing, accessibility, and a complete endgame build walkthrough.
Programming & CSMaster every keypad — 10-key numeric, T9 phone, hex, calculator, ATM/POS, banking & teller, medical & clinical data entry, warehouse scanners, hardware locks/safes/cars, MIDI pads (MPK, Launchpad, Push, Maschine), drum machines (MPC, SP-404, TR-808/909), stenography, Braille, custom QMK/ZMK macropad building, and PIN security / shoulder-surfing defense. Touch-typing drills, KPH speed training, accuracy, and ergonomics.
LanguageThe language of Cambodia — script, grammar, Angkor Wat, Cambodian history, Apsara dance, and cuisine.
OthersYarn, hooks, needles, stitches, and patterns — first scarf to amigurumi, garments, lace, Fair Isle / Aran / Selbu / Andean / Lopapeysa / Japanese chart traditions, spinning your own yarn, dyeing (acid & natural), beaded work, machine knitting, pattern design, and selling your work.
OthersEvery knot you need — stoppers, bends, loops, hitches, lashings, decorative, climbing, sailing & rescue, fishing, macramé, scout pioneering, paracord, boating, arborist tree-work, and knot theory & topology.
Programming & CSBuild Android apps with Kotlin — null safety, coroutines, Jetpack Compose, Room, networking, architecture, Play Store, and real apps.
LanguageSpoken by 20 million Kurds — script, grammar, Newroz, Kurdish history, music, Sorani & Kurmanji dialects.
ScienceExplore the universe, life, and everything in between — from black holes to immune cells, quantum physics to climate change. 360 lessons.
LanguageClassical Latin from scratch — five declensions, four conjugations, full grammar (gerunds, supines, deponents, every subordinate clause, every case use), prosody & meter, the entire canon (Plautus, Terence, Catullus, Horace, Lucretius, Sallust, Livy, Tacitus, Suetonius, Pliny, Seneca, Quintilian, Caesar, Cicero, Virgil, Ovid), ecclesiastical & legal Latin, medieval & Neo-Latin, vulgar Latin and Romance roots.
FestivalCarnaval (Rio & Salvador), Día de los Muertos, Inti Raymi, Las Fallas, Fiesta de la Vendimia, Festa Junina, La Tomatina, Semana Santa — origins, music, dance, food, costumes, religious roots, and the cultural meaning behind each celebration across Latin America.
LanguageThe official language of Latvia — one of the oldest surviving Indo-European languages. 1.5+ million speakers.
Science💡 From photons to chandeliers — the physics of light AND the craft of lighting design. Reflection, refraction, diffraction, the EM spectrum, the human eye and color, incandescent & fluorescent & LED & laser, photometry, stage & film & architectural lighting, smart lighting, light pollution, fiber optics, and the future of illumination.
MathVectors, matrices, and the geometry of equations — vector spaces, linear transformations, eigenvalues & eigenvectors, determinants, orthogonality, SVD, PCA, and applications in graphics, ML, and quantum mechanics.
Programming & CSMaster the Linux command line — files, permissions, processes, pipes, Bash scripting, text tools, networking, systemd, and automation.
LanguageThe official language of Lithuania — considered the most archaic living Indo-European language. 3+ million speakers. Includes deep dives into pagan mythology (Romuva, Perkūnas, sutartinės), Lithuanian cities & regions (Vilnius, Kaunas, Klaipėda, Trakai, Curonian Spit), and 700 years of independence plus the global diaspora.
LogicMaster logical reasoning through puzzles — from ordering and negation to quantifiers and optimization.
LogicLearn to reason with Venn diagrams, set operations, and formal arguments. Build the language of logic.
LogicStrengthen deductive and inductive reasoning skills. Build airtight arguments and spot logical fallacies.
Programming & CSRoblox's gradually-typed Lua dialect — Roblox Studio, the full object model, RemoteEvents, DataStores, ScreenGui design, TweenService, animations, ModuleScripts, pathfinding, particles, and publishing/monetizing your own Roblox games.
OthersReality checks, dream journaling, WILD & MILD techniques, dream stabilization & control, Tibetan dream yoga.
Programming & CSLearn machine learning — data prep, regression, classification, neural networks, deep learning, NLP, model evaluation, and real ML projects.
OthersStage and close-up magic — card tricks (forces, controls, palms, memorized decks), coin magic (matrix, coins across, spellbound), bill magic, rubber band, sponge ball, cups & balls, mentalism (book tests, billets, PK), rope, stage illusions, escape acts (Houdini), modern magicians (Copperfield, Penn & Teller), bizarre magic, kids/restaurant/trade-show shows, theory (Tamariz, Vernon), and building your full act.
LanguageBuild a conlang from scratch the way Tolkien, Marc Okrand, and David J. Peterson do — full foundations (phonology, morphology, syntax, alignment, lexicon, sound change, writing systems), deep dives into Quenya/Sindarin/Klingon/High Valyrian/Dothraki/Esperanto/Lojban/Toki Pona/Ithkuil, specialized topics (numerals, color terms, kinship, honorifics, evidentiality, noun classes, classifiers, vowel harmony, tones, clicks, sign & whistled conlangs, pidgins & creoles), worldbuilding, sociolinguistics, translation, reference grammars, dictionaries, conlang for film/TV/games, and the conlang community.
LanguageThe only Semitic language written in Latin script — and the only Semitic EU language. ~500,000 speakers across Malta & Gozo. Descended from Siculo-Arabic with Italian, Sicilian & English borrowings. Pharyngeal consonants (ħ, għ), broken plurals, unique letters Ċ Ġ Ż. Not taught by Duolingo.
LanguageThe language of the Mandalorians from Star Wars — Karen Traviss's creation. Phonology, alphabet, grammar, family vocabulary, the Resol'nare, battle phrases, and full cultural fluency.
LanguageThe Polynesian language of New Zealand's indigenous Māori people — co-official with English and growing rapidly. Rolling vowels, glottal stops, deep cultural concepts (whakapapa, mana, whenua, manaakitanga), haka, waka, marae, kaupapa Māori. Not taught by Duolingo.
ScienceLife in the oceans — coral reefs, deep-sea creatures, marine mammals, sharks, plankton, ocean ecosystems, hydrothermal vents, marine conservation, and the abyssal zone.
OthersThe world's combat traditions — striking, grappling & weapons. Stances & footwork, basic strikes, Western boxing, karate (kata, kihon), taekwondo, kung fu, Wing Chun, tai chi, judo (throws & newaza), Brazilian jiu-jitsu (guard, mount, submissions), wrestling (freestyle & Greco-Roman), sambo, Muay Thai, kickboxing, MMA, Krav Maga, capoeira, aikido, ninjutsu, kendo, iaido, Filipino Eskrima/Arnis, ancient Greek pankration, the Shaolin Temple, Bruce Lee & Jeet Kune Do, UFC history (Royce Gracie to McGregor), Olympic combat sports, self-defense, conditioning & recovery, and the lifelong path of mastery.
Math5,000 years of mathematical discovery — from Babylonian tablets to the Millennium Problems. Meet the minds who shaped mathematics.
MathEvery symbol you'll ever read in math — sets, logic (negation, quantifiers, implication), calculus, Greek letters, geometry, functions, number theory, linear algebra, topology, group theory, category theory, tensors, complex & functional analysis, measure theory, graph & information theory, complexity, cryptography, Dirac quantum notation, and beyond.
OthersAnalyze political claims, spot propaganda, evaluate sources, understand rhetoric (Aristotle to Burke), framing & metaphor, doublespeak & euphemisms, the cable/talk-radio/podcast/newsletter ecosystem, false balance, selective editing, journalism ethics & landmark cases (Watergate, Pentagon Papers, Iraq WMD), political comedy & cartoons, public broadcasting, news deserts, media ownership, Section 230, and verification tools (reverse image, InVID, C2PA provenance).
ScienceBecome medically literate — anatomy by system, physiology, pharmacology, pathology, every clinical specialty from cardiology to psychiatry, surgery, emergency, radiology, public health, medical ethics, the history of medicine, and a deep dive into medical math — dosage & IV calculations, BMI, GFR, ABG, cardiac & pulmonary formulas, diagnostic stats, and pharmacokinetics.
OthersPractical meditation — breath, body, loving-kindness, mantra, movement, Zen, MBSR (Jon Kabat-Zinn's 8-week program), modern apps (Headspace, Calm, Insight Timer, Waking Up), meditation for children & teens, plus quick daily sessions for busy schedules.
OthersTrain your memory like a world-champion mnemonist. Build memory palaces (Method of Loci), master the Major System & Person-Action-Object, memorize a deck of cards in under a minute, recite π to a thousand digits, learn names & faces, ace exams without cramming, deliver speeches without notes. Plus the science of forgetting (Ebbinghaus), spaced repetition, sleep consolidation, false memories, eyewitness testimony, eidetic-memory myths, and the lives of memory athletes from Tony Buzan to Joshua Foer to Dominic O'Brien.
ScienceHow weather works — pressure, humidity, clouds, hail storms, hurricanes, tornadoes, blizzards, monsoons, lightning deep dive, atmospheric optics, fog, frost, heat waves, drought, air quality, ozone, marine & aviation meteorology, microclimates, weather modification, NWP, satellite met, plus weather across the solar system (Mercury, Venus, Mars, Jupiter, Saturn, Uranus, Neptune, Titan, Pluto) and exoplanet weather (hot Jupiters, iron rain, glass rain, JWST atmospheres).
ScienceThe microbial world — bacteria, archaea, viruses, fungi, the human microbiome, antibiotics & resistance, vaccines, fermentation, and microbiology lab techniques (Gram staining, PCR).
Music🥁 Learn beat-making and finger drumming on a MIDI pad — the Duolingo way. Tap a real 16-pad drum grid right in your browser, then build grooves one genre at a time: hip-hop, boom bap, trap, lo-fi, house, techno, drum & bass, dubstep, afrobeats, amapiano, reggaeton, funk, jazz swing and more, finishing with classic breakbeats like the Amen Break. 6 lessons per unit.
MathPuzzles, paradoxes, infinity, number theory, fractals, cryptography, and the strangest ideas in mathematics.
Programming & CSBuild iOS & Android apps — Swift, SwiftUI, Kotlin, Jetpack Compose, React Native, Flutter, mobile UX, networking, persistence, push notifications, and App Store / Play Store deployment.
LanguageThe official language of Mongolia — from Cyrillic script and traditional Bichig to advanced reading, writing, and cultural mastery.
OthersThe math, business, psychology, and strategy behind the world's biggest YouTuber. From viral videos to Feastables.
MusicNotes, scales, chords, rhythm, harmony, and composition — understand the language of music.
Music🎵 Learn music the Duolingo Music way. Start with Unit 1: Basics Piano (middle C, finger numbers, posture, dynamics, reading the staff), then learn one song at a time — phrase by phrase, drilling rhythm, then a full performance. From "Twinkle, Twinkle Little Star" to "Clair de Lune", "Let It Go", "Bohemian Rhapsody", "Vivir Mi Vida", "Despacito", "Bésame Mucho", "Gasolina", "Mi Gente", "Tusa", "Chan Chan", "Corazón Partío", and 150+ more.
OthersGods, heroes, monsters, and legends from every corner of the world — Greek (pantheon, Titans, Heracles, Odysseus, Trojan War, monsters, tragedy), Roman, Norse (Aesir, Vanir, Ragnarok, Loki), Egyptian (creation, Osiris cycle, Duat), Mesopotamian, Hindu (Ramayana, Mahabharata), Buddhist, Chinese, Japanese, Korean, Aztec, Maya, Inca, African (Yoruba), comparative themes (Hero's Journey, flood myths, tricksters), and modern culture.
ScienceExplore the circuits behind NASA's telescopes, rockets, rovers, satellites, and space stations. Real space engineering.
LanguageThe language of the Na'vi from Pandora in Avatar — created by Paul Frommer. Ejectives, agglutinative infixes, octal numbers, tripartite alignment, tsaheylu, and songs of the Omatikaya and Metkayina clans.
OthersBATNA, anchoring, active listening, win-win strategies, salary, real estate, international, hostage-negotiation principles.
ScienceNeon signs, lasers, LEDs, plasma, fiber optics, holograms, UV, X-rays, bioluminescence, spectroscopy, solar energy, and relativity.
LanguageThe official language of Nepal — Devanagari script, grammar, culture, trekking, and Himalayan life.
ScienceHow the nervous system works — neurons, synapses, action potentials, neurotransmitters, brain anatomy, vision & hearing, motor control, memory, emotion, sleep, neurological disorders, neuroplasticity, brain-computer interfaces, and how high IQ works (P-FIT, neural efficiency, frontoparietal network).
Others🤖 Forty-five escalating CAPTCHA-style challenges — from "check the box" to "cry on command" — a tribute to Neal Agarwal's neal.fun/not-a-robot 45 levels. Prove your humanity one impossible test at a time.
MathEvery number ever named — from zero to googolplex, Graham's number, TREE(3), transfinite ordinals, large cardinals, and absolute infinity.
MathFrom tally marks to hexadecimal — binary, octal, hex, ternary, dozenal, sexagesimal, vigesimal, balanced ternary, base φ, negative bases, Roman, Mayan, Egyptian, Chinese, and Arabic numerals, with addition, subtraction, multiplication and division drills in every base.
LanguageSpeak Anishinaabemowin — the Algonquian language of the Great Lakes and Canadian Subarctic. Sounds, the double-vowel system, animate vs inanimate grammar, family, hunting & seasons, Seven…
OthersThe Japanese art of paper folding — papers (kami, washi, foil, lokta), classic cranes, mathematical origami (Maekawa & Kawasaki theorems, crease patterns, Yoshizawa-Randlett system), masters (Yoshizawa, Lang, Tomoko Fuse), insects, birds, mammals, sea creatures, dragons, box-pleating, stars, boxes, hearts, action models, holiday folds, tessellations, kusudama, pop-ups, plus origami in space (Miura fold, NASA telescope) and medicine (heart stents).
OthersFrom a blank canvas to a finished painting — color theory, the color wheel, drawing as foundation, materials, watercolor (washes, glazing, wet-on-wet), gouache, acrylic, oil (fat over lean, underpainting), composition (rule of thirds, golden ratio), perspective, light & shadow, atmospheric perspective, still life, landscape, portraiture, figure painting, plein air, the Renaissance (Leonardo, Michelangelo, Raphael), Baroque (Caravaggio, Rembrandt, Vermeer), Impressionism (Monet, Renoir, Degas), Post-Impressionism (Van Gogh, Cézanne, Gauguin), Cubism & Picasso, Surrealism (Dalí, Magritte), Abstract Expressionism (Pollock, Rothko), Chinese ink & wash, Japanese ukiyo-e, Indian & Persian miniatures, African & Indigenous art, encaustic, tempera & fresco, and modern digital media.
Data AnalysisPython's most-used data library — NumPy foundations, Series & DataFrame, reading CSV / Excel / JSON / Parquet / SQL, indexing (loc, iloc, boolean masks), .query(), missing data (NaN, fillna, dropna), dtypes & .astype, vectorized math, .apply / .map, groupby & aggregation, pivot & pivot_table, melt & wide-vs-long, merge & join, MultiIndex & .stack/.unstack, time series (.resample, .rolling, .shift), categorical dtype, string accessor .str, .cut & .qcut, window functions, performance (chunked reads, eval, query, Polars vs Pandas, PyArrow, Dask, Modin, cuDF on GPU), plotting with .plot & hvplot, styling, exporting, and Pandas 2.x copy-on-write.
LogicClassic logical paradoxes, math puzzles, brain teasers, and thought experiments that challenge your reasoning.
LanguageLearn Pashto — spoken by 60 million Pashtuns in Afghanistan and Pakistan. Written in Perso-Arabic script. 169 lessons across 13 units.
ScienceThe microscopic world that causes disease — bacteria, viruses, fungi, parasites, prions, the immune system, vaccines, antibiotics, pandemics, and epidemiology.
LanguageThe language of Rumi and Hafez — script, grammar, poetry, Nowruz, Iranian history, Dari & Tajik dialects.
OthersTake control of money — budgeting, saving, debt payoff, credit scores, stocks, bonds, ETFs, index funds, retirement (401k, IRA), real estate, taxes, and FIRE financial independence.
OthersEthics, epistemology, metaphysics, political philosophy, logic, philosophy of mind, religion, science, math, physics, biology, technology, education, law — plus free will, consciousness, personal identity, time, metaethics, bioethics, environmental & animal ethics, feminist philosophy, philosophy of race, postmodernism, pragmatism, stoicism, and deep dives into Indian and Chinese traditions.
OthersExposure triangle, composition, lighting, portraits, landscapes, post-processing — plus 12 deep-dive units on phone photography (iPhone ProRAW & ProRes, Pixel/Samsung/Xiaomi cameras, computational photography, night mode, phone lenses, portrait & cinematic mode, 4K/Dolby Vision video, Lightroom Mobile, Snapseed, VSCO, gimbals & mics, pro phone workflow), genre deep dives (wedding, wildlife, sports, macro, astro, architecture, food, concert), studio & off-camera flash, long exposure, HDR, Lightroom & Photoshop, color grading, and print/display.
ScienceFrom mechanics to relativity to quantum — Newton's laws, energy & momentum, waves, sound, optics, electromagnetism (Maxwell's equations), thermodynamics, special & general relativity, quantum mechanics, and particle physics.
LanguageThe universal visual language — pictograms, hieroglyphs, emoji, Blissymbolics, road signs, ISOTYPE, icons, AAC, heraldry, religious symbols, rock art, body language, photography, propaganda, and reading the world without words.
OthersFrom clay to kiln — clay chemistry (earthenware, stoneware, porcelain, terracotta), pinch/coil/slab building, full wheel mastery (centering, cylinders, bowls, plates, mugs, teapots, lidded forms, bottles), trimming, altered forms, sgraffito, slip trailing, mishima, carving & piercing, stamping, underglazes, glaze chemistry & cones, ash glazes, salt/soda/wood/anagama firing, electric & gas kilns, raku & naked raku, pit firing & saggar, sculpture, figurative & architectural ceramics, mosaic — plus a 20-lesson business capstone.
Data AnalysisMicrosoft's flagship BI tool — Desktop / Service / Mobile / Report Server, connecting to data (CSV, Excel, SQL Server, Snowflake, BigQuery, REST APIs), Power Query M language for ETL, the data model (star schema, fact & dimension tables), relationships, DAX deep dive (calculated columns vs measures, row context vs filter context, CALCULATE, FILTER, ALL, time intelligence), visuals (bar, column, line, map, matrix, KPI), bookmarks & drillthrough, sync slicers, custom visuals, mobile layouts, paginated reports (RDL), incremental refresh, gateways, workspaces & apps, row-level security (RLS), deployment pipelines, Power BI Embedded, integration with Power Automate / Apps / Teams, Copilot for Power BI, and PL-300 certification prep.
Data AnalysisBayesian networks, XGBoost, ARIMA, Prophet, forecasting, ensemble methods, and ethical prediction.
Data AnalysisBayes theorem, distributions, hypothesis testing, A/B testing, Monte Carlo, and Markov chains.
Programming & CSThe complete history of computing — from the abacus to AI. Pioneers, machines, languages, the internet, open source, cybersecurity, and the digital revolution.
LogicDirect proof, contradiction, induction, contrapositive, construction, and advanced proof methods for math.
ScienceMemory, emotions, behavior, personality & social psych — plus deep dives on Freud, Jung, Piaget, Vygotsky, Bandura, Milgram, Asch, Kahneman; MDD, anxiety, PTSD, OCD, bipolar, schizophrenia, personality disorders, autism, ADHD, eating disorders, addiction; CBT, DBT, ACT, EMDR; replication crisis, statistics, reading papers, forensic, sport, evolutionary, cross-cultural — plus a career capstone.
OthersSpeak with confidence — basics (stage fright, projection, body language, eye contact, mic), then deep dives into Aristotle, Cicero, Quintilian, modern rhetoric, rhetorical devices, storytelling frameworks, speechwriting, voice & diction, accent reduction, slide design, webinars, podcasting, interview skills, crisis comms, press conferences, negotiation, sales & investor pitching, elevator pitches, weddings/funerals/religious/political speaking, motivational speaking, after-dinner, stand-up, debate formats (LD/Policy/PF/Parli/World Schools), famous orators, famous-speech analysis, and a 28-lesson capstone on building a speaking career.
LanguageSpeak Panjabi — the Indo-Aryan language of Punjab in India and Pakistan. Gurmukhi script, Shahmukhi overview, greetings, grammar, numbers, family, food, Sikhism, Bhangra & Bollywood, and the…
Others🧩 Master jigsaw puzzles from a 4-piece wooden board up to a 5,000-piece marathon. Edge strategy, color sorting, sky-handling, the canonical 1,000-piece adult tier, specialty puzzles (Wasgij, Krypt, 3D), and World Jigsaw Puzzle Championship speed-solving.
Programming & CSLearn Python from scratch — variables, loops, functions, OOP, file I/O, APIs, web scraping, data science, GUI, databases, algorithms, and real projects.
Data AnalysisMaster both types of data — surveys, interviews, experiments, statistics, mixed methods, and real-world data applications.
Programming & CSDive into qubits, superposition, entanglement, quantum gates, algorithms, and real quantum hardware.
LanguageThe Indigenous Andean language family of the Inca Empire, spoken by 8–10 million across Peru, Bolivia, Ecuador, Argentina, Chile & Colombia. Co-official in Peru & Bolivia. Agglutinative grammar, uvular consonants (q), evidentiality markers (-mi, -si, -chá), and the language of Tahuantinsuyu. Not taught by Duolingo.
Data AnalysisThe statistics-first language — base R basics, vectors, factors, lists, data frames, the RStudio IDE, R Projects, R Markdown / Quarto, the tidyverse (dplyr, tidyr, readr, purrr, stringr, lubridate, forcats), the pipe (|> and %>%), ggplot2 (geoms, scales, themes, facets), data import (read_csv, readxl, haven, googlesheets4), joins & pivots, summarising & group_by, mutate, slicing & arrange, tibbles, dates & times, strings & regex, factor manipulation, functional programming with purrr, tidymodels (rsample, recipes, parsnip, yardstick, workflows), statistical modeling (lm, glm, mixed models, GAM), survival analysis, time series (forecast, fable), Shiny dashboards, plotly, leaflet, sf for geospatial, data.table speed alternative, arrow & Parquet, reproducible reports, and package development (devtools, testthat).
LogicCognitive biases, Bayesian reasoning, decision theory, and the art of being less wrong.
Data AnalysisLinear, multiple, polynomial, ridge, lasso, logistic regression, residuals, and diagnostics.
OthersMathagram is a safe place for learning. A course on slurs, hate speech, why words hurt, online respect, and being an ally — taught by Edam (still furious).
LanguageThe official language of Romania and Moldova — the only Romance language in Eastern Europe. 26+ million speakers.
OthersSolve the cube in seconds — beginner method, full CFOP, alternative methods (Roux, ZZ), big cubes, blindfolded, one-handed, competition prep.
Programming & CSLearn Rust — ownership, borrowing, lifetimes, traits, enums, error handling, concurrency, async, cargo, and real systems projects.
OthersHarness the wind — anatomy of a sailboat, points of sail, sail trim, tacking & jibing, COLREGS rules, essential knots, mooring & anchoring, man-overboard, heavy weather & reefing, navigation (charts, dead reckoning, GPS), tides & currents, marine weather, the Beaufort scale, VHF radio & MAYDAY, dinghies (Laser, Optimist), keelboats, catamarans, cruising & bluewater, racing tactics, the America's Cup, the Vendée Globe, Captain Cook, Joshua Slocum, Polynesian wayfinding, the Age of Sail, foiling yacht design, and life at sea.
OthersThe complete history of education — from ancient academies to modern classrooms. How schools began, the fight for equal education, testing, technology, and the future of learning.
Programming & CSThe terminal as it appears in science fiction — and the real CLI tools that make your shell look (and work) like a starship console. cmatrix, neofetch, htop/btop, nmap, Wireshark/tcpdump, SSH, tmux, Vim, Emacs, ASCII art, LCARS theming, oh-my-zsh, fzf/ripgrep, AI in the terminal — plus dotfiles, macOS/Windows terminals, hacker distros (Kali, Parrot, Tails, Qubes), Termux/iSH, JSON/API tools, database CLIs, Docker/Kubernetes, Git/GitHub CLI, CI/CD, modern Vim/Neovim/Helix, ed/AWK/sed/Bash deep dives, reverse engineering (radare2, Ghidra), cryptography (gpg, age, openssl), privacy (Tor, Tailscale), and a Hollywood-worthy demo reel capstone.
ScienceThe real science behind sci-fi — space travel, AI, aliens, time travel, multiverse, robots, Star Wars, cyberpunk, and how fiction becomes reality.
SciencePhysics, chemistry, biology, earth science, astronomy puzzles, paradoxes, and speed rounds.
ScienceHypothesize, experiment, and reason like a scientist. Includes gears, mechanics, structures, and electricity.
LanguageLallans — the Lowland Scots language. From everyday "Whit's the craic?" to Burns's poetry. Phonology (rolled r, /ʍ/, vowel system), pronouns (ye/youse), modal verbs, irregular verbs, distinctive vocabulary (bairn, dreich, glaikit, blether), regional dialects (Doric, Glaswegian, Borders, Shetland, Orcadian, Ulster Scots), spelling traditions, the Scots Wikipedia debate, Scots in literature (Burns, Stevenson, Lochhead, Welsh), Scots in song & comedy, official recognition under the European Charter, and modern revival efforts.
Programming & CSMIT's block-based visual coding — sprites, platformers, top-down arcade games, animation, generative art, interactive stories, Thinking in Code, Scratch extensions, physics simulation, AI/ML in Scratch, cloud multiplayer, classroom teaching, community remixing, and transitioning to Python & JavaScript.
LanguageThe official language of Serbia — written in both Cyrillic and Latin script. A South Slavic language with 12 million speakers.
LogicSets, operations, relations, functions, cardinality, ordinals, cardinals, and the axioms of ZFC.
LanguageLearn Shiddin — script, grammar, culture, traditions, dialects, crafts, and full fluency.
MusicTrain your voice — anatomy, breathing (diaphragmatic), pitch, ear training, range extension (chest, head, mix, falsetto), vibrato, harmony, vocal health, microphone technique, performance, recording, genres (classical, pop, rock, R&B, country, musical theater, opera, jazz), and famous voice coaches.
LanguageThe language of Sri Lanka — rounded script, grammar, Buddhist culture, Sigiriya, and Sri Lankan cuisine.
ScienceWhy we sleep — circadian rhythms, REM and deep sleep, dreaming, insomnia, sleep apnea, jet lag, sleep tech, and the science of sleeping better.
OthersDMCA copyright removal, callout post rules, evidence docs, cyberbullying, privacy, scams, predators, platform rules — plus a full unit on reporting misconduct (recognizing grooming/harassment, documenting evidence, reporting on Mathagram, Discord, Roblox, Instagram, TikTok, to schools and law enforcement, NCMEC CyberTipline) and a unit on responsible reporting (defamation, false reports, mandatory reporters, retaliation, escalation).
ScienceExplore soil formation, texture, chemistry, biology, and the role soil plays in agriculture, ecosystems, and climate.
LanguageEl segundo idioma nativo más hablado del mundo — 500+ million speakers across Spain, México, Argentina, Colombia, Perú, Chile, Cuba & 17 other countries. Subjunctive mood, ser-vs-estar, por-vs-para, regional voseo & vosotros, flamenco & Latin music, García Márquez & Borges. From hola to fluency.
Language★ RecommendedMaster Spanish grammar, all verb tenses, subjunctive (with adverbial-clause decision tree), pasiva refleja, perífrasis verbales avanzadas, acentuación (agudas/llanas/esdrújulas, diptongos, hiatos, sinéresis), regional dialects (rioplatense, caribeño, andino, mayense, panameño, costarricense, guineoecuatoriano, filipino chabacano, spanglish), 700+ difficult vocab, idioms, proverbs, DELE C2, AP Spanish, and deep dives into Neruda, Paz, Fuentes, Bolaño, Azuela, Sor Juana, Lorca, Vallejo, Matute, Montero plus Spanish cinema (Almodóvar, Cuarón, del Toro).
Data AnalysisMaster spreadsheets — Excel, Google Sheets, formulas, pivot tables, VLOOKUP, macros, Power Query, and dashboard design.
Programming & CSMaster databases — SQL queries, joins, aggregation, schema design, normalization, indexing, transactions, NoSQL, and real data projects.
Data AnalysisQuery databases like a pro — SELECT, JOIN, GROUP BY, subqueries, window functions, and real-world data analysis with SQL.
Data AnalysisThink with data — descriptive stats, probability, distributions, hypothesis testing, confidence intervals, and real-world applications.
OthersStock basics, financial statements, valuation (P/E, P/B, DCF), ETFs, trading, options & Greeks, bonds, portfolio construction, behavioral finance, REITs, forex, commodities, futures, international & emerging markets, growth vs value, Buffett/Munger/Lynch/Graham/Dalio approaches, tax-advantaged accounts, tax-loss harvesting, brokerage walkthroughs (Schwab/Fidelity/IBKR/Robinhood), VIX & volatility, the 1929/1987/2000/2008/2020 crashes, and building a long-term portfolio.
OthersMaster how to learn — note-taking, memory techniques, focus, exam strategies, and a full Time Management & Productivity track (GTD, Pomodoro, Time Blocking, Deep Work, OKRs, Atomic Habits, Indistractable, Eat That Frog, 7 Habits, 12-Week Year, Make Time, Flow, Energy & Sleep, Procrastination Science, Saying No, Meeting & Notification Hygiene).
LanguageSpoken by 40 million in West Java. Rich in wayang, angklung, gamelan, and Sundanese cuisine.
ScienceThe science of staying alive — shelter, fire, water chemistry, foraging, hunting, tracking, primitive bushcraft, wilderness medicine, navigation, weather reading, every climate & disaster (earthquake, hurricane, tornado, flood, wildfire, tsunami, volcanic, avalanche, pandemic, nuclear), urban survival, and bug-out planning.
LanguageKaribu! Learn Swahili (Kiswahili) — noun classes, verb morphology, conversation, and East African culture.
Programming & CSBuild iPhone apps with Swift — optionals, protocols, SwiftUI, UIKit, networking, Core Data, concurrency, the App Store, and real apps.
Data AnalysisThe classic visual analytics platform (now Salesforce) — Tableau Desktop / Public / Server / Cloud / Prep, connecting to data (live vs extract, .hyper), dimensions vs measures, blue vs green pills, Show Me, every chart type (bar, line, scatter, heat map, treemap, packed bubble, Sankey, sunburst, funnel, waterfall, box plot, histogram), maps (filled, point, custom geocoding, density), Level of Detail (LOD) expressions — FIXED / INCLUDE / EXCLUDE, table calculations, parameters & dynamic dashboards, sets & groups, dual-axis & combo charts, calculated fields, data blending vs joining vs relationships, Tableau Prep for ETL, story points, dashboard actions, device-specific layouts, performance tuning, publishing to Server / Cloud, permissions, subscriptions & alerts, Tableau Mobile, Ask Data, Explain Data, Tableau Pulse, and Desktop Specialist certification.
OthersDungeons & Dragons, character creation, combat, storytelling, game mastering, worldbuilding, other systems, online RPG.
LanguageSpeak Tagalog — the basis of Filipino, the Philippines' national language. Sounds, focus & topic grammar, numbers, family, Manila life, food, history, and pop culture from Eraserheads to Pinoy…
ScienceHow animals communicate with their tails — squirrels, rabbits, mustelids, marsupials, lemurs, prehensile-tail monkeys, lizard autotomy, crocodilians, rattlesnakes, big cats (lion tassel, tiger, cheetah, leopard), hyenas/foxes/coyotes, whale flukes, dolphins, sharks, stingrays, peacocks, raptors, songbirds, mythical tails, and pet tail care.
LanguageThe official language of Tajikistan — a Persian dialect written in Cyrillic. Grammar, literature, dialects, culture, and the Silk Road heritage.
LanguageAugmentative & Alternative Communication (AAC) — from letter boards to Stephen Hawking's DECtalk to modern eye-tracking SGDs. Symbol systems (PCS, Bliss, SymbolStix), picture boards, speech-generating devices, switch & eye-gaze access, Proloquo2Go / TouchChat / LAMP, core vs fringe vocabulary, aided language stimulation, TTS voices, and AAC for autism, ALS, cerebral palsy & stroke.
LanguageOne of the world's oldest living languages, spoken by over 80 million people in India, Sri Lanka, Singapore, and Malaysia.
OthersTarot decks, the Major & Minor Arcana, spreads (3-card, Celtic Cross), reversed cards, daily practice, reading for others.
LanguageThe most spoken Dravidian language. 18 units and 275 lessons — from basics to mastery.
LanguageThe official language of Thailand — tones, script, culture, and conversation. From สวัสดี to fluency.
LanguageSpoken in Eritrea & northern Ethiopia — Ge'ez script, grammar, Orthodox culture, Eritrean history.
Data AnalysisPredict the future from the past — decomposition (trend, seasonality, noise), stationarity & differencing, autocorrelation (ACF/PACF), exponential smoothing, Holt's linear trend, Holt-Winters seasonal, AR / MA / ARMA / ARIMA / SARIMA / ARIMAX, Box-Jenkins methodology, STL decomposition, anomaly detection, Prophet & NeuralProphet, LSTM & Transformer models, multivariate VAR, Granger causality, spectral & wavelet analysis, forecast accuracy (MAE, RMSE, MAPE, MASE), backtesting, and real applications (sales, energy, weather, epidemic curves, finance) plus tools (statsmodels, fable, Prophet).
MathUnderstand angles, triangles, and periodic functions. See how trig connects geometry to the real world.
LanguageSpeak Akan Twi — Ghana's most widely spoken language. Tones, greetings, grammar, numbers, the Ashanti kingdom, Adinkra symbols, Highlife & Hiplife, and Anansi proverbs.
Programming & CSAdd static types to JavaScript — interfaces, generics, narrowing, utility types, declaration files, decorators, and real full-stack projects.
Programming & CSTyping Skill touch typing — keys introduced one finger at a time. Find F & J home bumps, add D/K, S/L, A/;, master the home row, then E/I, R/U, T/Y, O/W, M/V, C/comma, X/period, N/B, and Q/P/Z/slash. Then capitalization, numbers, punctuation, symbols, speed & accuracy drills, real-world sentences. Plus a Unit-1 personalized practice lesson ("Fill the Missing Keyboard") that adapts to the keys you struggle with, a Spanish-typing unit (ñ, dead-key acute accents á é í ó ú, ¿ ¡, ü, ISO layout) and deep dives in Python (data structures, Django/Flask, NumPy/Pandas), TypeScript, Swift, Kotlin, PHP, R, MATLAB, LaTeX, Assembly, Haskell/Elixir, React/Vue/Angular, Tailwind/Sass, Vim motions, Linux/Docker/Kubernetes/AWS CLI, math/chess/chemistry/music notation.
Programming & CSLearn the Unity game engine — GameObjects, C# scripting, physics, UI, animation, 2D/3D games, multiplayer, AR/VR, and publishing. 375 lessons across 25 units.
LanguageLearn Urdu — the beautiful Nastaliq-scripted language spoken by over 230 million people in Pakistan and India. From the alphabet to fluency.
LanguageLearn Uzbek — a Turkic language spoken by 35 million people. Silk Road heritage with deep dives into phonology, vowel harmony, six cases, verb aspect & mood, Tashkent, Samarkand, Bukhara, Khiva, Fergana, Karakalpakstan & the Aral Sea, plov, manti, lagman, choyhona tea culture, non bread, madrasa architecture, suzani crafts, dutar & maqom music, Alisher Navoi literature.
MathBrilliant-style vectors deep dive — magnitude & direction, components, addition, dot & cross products, projections & decomposition, lines & planes in 3D, polar/cylindrical/spherical coordinates, linear combinations & span, linear independence, basis & dimension, norms & distance, vector-valued functions, gradient/divergence/curl preview, plus applied units on physics, computer graphics, and machine learning vectors.
OthersPixels, aspect ratios, SD → 8K, frame rates, bitrate & compression, codecs (H.264 / H.265 / AV1), HDR (Dolby Vision / HDR10 / HLG), color depth & spaces (Rec.709 / Rec.2020 / DCI‑P3), interlaced vs progressive, cinema anamorphic, upscaling & downscaling, and streaming-platform workflows.
OthersVideo editing companies, online editors, professional tools, and the business of video production. 375 lessons across 25 units.
OthersMicrosoft Visio — flowcharts, swimlanes, org charts, network diagrams, floor plans, BPMN, UML, AWS & Azure architecture, data-linked shapes, custom stencils, Visio for the Web, and integration with Teams, SharePoint, Word, and Excel.
Data AnalysisMaster Microsoft Viva Insights — workplace analytics, productivity data, wellbeing, collaboration patterns, meeting culture, focus time, ONA, burnout detection, Power BI templates, Microsoft Graph queries, Teams & Outlook analytics, Viva Learning, Goals, Topics, Sales, Pulse, Copilot AI insights, predictive attrition models, and industry-specific implementations.
Programming & CSBuild websites from scratch — HTML, CSS, JS, frameworks beyond React (Svelte, Solid, Astro, Remix, Qwik), Web Components, WASM, Canvas, SVG, Three.js, WebGL shaders, D3, design systems, Storybook, Playwright, Vitest, state libraries, GraphQL, tRPC, Server Components, edge functions, Bun & Deno, monorepos, WebAuthn passkeys, payments, headless CMS, and realtime.
LanguageSpeak Western Armenian — the diaspora dialect of Lebanon, Syria, Istanbul, Los Angeles, Paris and beyond. Mesropian alphabet, distinct pronunciation from Eastern Armenian, grammar, diaspora…
Others🔍 The world's most famous striped-shirt traveler — and his friends Wenda, Wizard Whitebeard, Odlaw & Woof. Find Waldo on every single page of all four classic Martin Handford books: the 1987 original (172 pages of beachfronts, museums, train stations & ski slopes), Where's Waldo Now? (32 pages back in time — Stone Age, Egyptians, Romans, Vikings), The Great Waldo Search (26 pages of Gobbling Gluttons, Battling Monks, Underwater Wars & the Land of Waldos), and Where's Waldo in Hollywood (32 pages on movie sets — Robin Hood, swordfights, the future).
OthersGrapes, regions (Old World & New World), tasting technique, reds, whites, sparkling & champagne, food pairings.
LanguageThe lingua franca of Senegal, the Gambia & Mauritania — 12+ million speakers. Phonology (prenasalized stops, geminates, ATR vowel harmony), Latin & Wolofal (Arabic-script) writing, all eight noun classes, aspect & focus markers, pronouns, verb morphology, time & numbers, greetings (Nanga def?), Dakar vs rural varieties, Mouride & Tijaniyya Sufi traditions, Youssou N'Dour mbalax, thiéboudienne & yassa cuisine, laamb wrestling, diaspora communities, Wolof literature, and Senegalese daily life.
OthersShop safety, wood ID (hardwoods, softwoods, engineered, reclaimed), drying & movement science, hand-tool sharpening, workbench building, dust collection, deep joinery (mortise & tenon, dovetail, Japanese, timber framing), bandsaw/router/CNC mastery, lathe (bowl, pen, spindle), carving (whittling, spoon, relief, chip), furniture styles (Shaker, MCM, Mission), cabinet & drawer making, chair making, wood bending, inlay & marquetry, pyrography, finishing, and selling.
Others🔎 Master word search puzzles from 10-word beginner grids up to 100-word marathons (the Crayons & Cravings 100-word tier). Letter-scan techniques, diagonal & backwards directions, hidden-message extraction, and tournament speed solving.
OthersFrom ancient civilizations to the future of humanity — empires, revolutions, wars, food history, and what comes next.
OthersFaith and meaning across human cultures — indigenous & animist traditions, ancient Mesopotamian, Egyptian, Greek, Roman & Norse polytheism, Hinduism, Jainism, Buddhism (Theravada, Mahayana, Vajrayana, Zen), Sikhism, Confucianism, Daoism, Shinto, Zoroastrianism, Judaism (Rabbinic, Hasidic, Reform), Christianity (Catholic, Orthodox, Protestant, Pentecostal), Islam (Sunni, Shia, Sufism, Five Pillars), Bahá'í, new religious movements, atheism & secular humanism, comparative themes, modern pluralism & conflict, and the future of faith.
OthersAsanas, breath, mobility — Hatha, Vinyasa, Ashtanga, Iyengar, Bikram, Kundalini, Power, Aerial, Acro, Yin, restorative; calming body & breath, box breathing, pranayama deep dive, meditation, anatomy of spine/hips/shoulders/hamstrings, functional exercise, foam rolling, PNF, sport-specific stretching, therapeutic yoga, prenatal, senior & chair, kids, yoga nidra, chakras, Ayurveda, and the eight limbs of Patanjali.
LanguageA major Niger-Congo language spoken by 45+ million across southwestern Nigeria, Benin, Togo, and the diaspora (Brazil, Cuba, Caribbean — Lucumí/Santería tradition). Three tones (high, mid, low), nasalized vowels, rich oral literature, Nollywood cinema, and the cradle of Ifá divination. Not taught by Duolingo.