History

43 ideas, each explained on one page with a 60-second lesson you can play right there.

Barter Barter is a system of exchange where people trade goods or services directly for other goods or services without using money.
Bretton Woods system Learn how the Bretton Woods system pegged global currencies to the US dollar and gold, why it collapsed in 1971, and how it shaped modern finance.
Brewing Brewing turns grains, water, and yeast into beer through fermentation, a process practiced for at least 13,000 years.
Cato the Younger Cato the Younger was an influential, uncompromising Roman senator and Stoic philosopher during the fall of the Roman Republic.
Chiaroscuro Chiaroscuro is the artistic technique of using strong light and dark contrasts to model three-dimensional volume on a flat surface.
Clerestory A clerestory is a high wall section containing windows set well above eye level.
Comparative method Linguists use the comparative method to trace systematic sound changes across modern languages and reconstruct prehistoric ancestral tongues.
Divination Divination is a ritual practice that seeks insight or answers by reading signs, omens, or random patterns.
Dot-com bubble The dot-com bubble was a massive rise and sudden crash in the stock prices of internet companies during the late 1990s.
Economic bubble An economic bubble happens when asset prices surge far past their real fundamental value, driven by easy liquidity and market psychology.
Epictetus Epictetus was a Greek Stoic philosopher who taught that suffering comes from trying to control external events rather than our own actions.
Ergotism Ergotism is toxic poisoning caused by eating fungus-infected rye or grain.
Etymology Etymology is the scientific study of the origins of words and how their sounds and meanings change over time.
Fleur de sel Fleur de sel is a delicate crust of pyramid-shaped crystals that forms on the surface of evaporating seawater in coastal salt marshes.
Flying buttress A flying buttress is an outside stone arch that carries a vault's outward push to a separate pier, so Gothic walls could hold huge stained-glass windows.
Gaius Musonius Rufus Musonius Rufus was a 1st-century Roman Stoic who taught Epictetus, argued women need the same education as men, and was exiled by Nero.
Gold Standard A gold standard is a monetary system where the basic unit of currency is defined as a fixed quantity of gold.
Great Depression The Great Depression was a severe global economic downturn lasting from 1929 to 1939.
Greek mythology Greek mythology is the body of ancient folklore, rituals, and legends about gods and heroes, shaped by oral poets rather than a single sacred text.
History of English How Anglo-Saxon roots, Viking grammar, Norman French vocabulary, and the Great Vowel Shift formed modern English.
Laplace's Demon Laplace's Demon is a thought experiment about a hypothetical intellect that knows the exact position and motion of every particle in existence.
Marcus Aurelius Marcus Aurelius was a Roman emperor and Stoic philosopher who governed the Roman Empire from 161 to 180 AD.
Mattachine Society The Mattachine Society was one of the earliest gay rights organizations in the United States, founded in Los Angeles in 1950.
May 68 How a French student protest against university rules sparked a 10-million-worker general strike that nearly toppled Charles de Gaulle.
Meditations Marcus Aurelius wrote Meditations as a private journal of Stoic reflections while running the Roman Empire and leading military campaigns.
MKUltra MKUltra was a covert, illegal human experimentation program run by the CIA from 1953 to 1972 to test mind control and truth serums.
Norse mythology Norse mythology is the collection of myths and religious beliefs belonging to the pre-Christian North Germanic peoples.
Notre Dame Cathedral Notre Dame Cathedral is a medieval Catholic cathedral and basilica located on the Île de la Cité in Paris, France.
Odin Odin is the chief god of the Norse pantheon, ruling Asgard and overseeing war, death, and poetry.
Philosophy Philosophy is the systematic study of fundamental questions about existence, knowledge, reason, mind, and values.
Proto-Germanic Proto-Germanic is the unrecorded ancient ancestor of English, German, and Norse, reconstructed purely through sound shifts and early loans.
Proto-Indo-European Proto-Indo-European is the prehistoric, unwritten ancestor language of modern tongues like English, Spanish, Russian, and Hindi.
Rib vault A rib vault is an arched ceiling frame made of crossed stone ribs filled in with thin masonry panels.
Romanesque architecture Romanesque architecture is a medieval European building style defined by thick stone walls, sturdy pillars, and semicircular arches.
Sea salt Sea salt is salt produced directly by evaporating seawater, either through open-air solar pans or fueled heat.
Seneca the Younger Seneca the Younger was an ancient Roman Stoic philosopher, statesman, and dramatist who served as the tutor and political advisor to Emperor Nero.
Sound Shift A sound shift is a permanent change in how a speech sound is pronounced across an entire language over time.
Space Exploration Space exploration is the physical investigation of outer space using uncrewed robotic probes and human spaceflight.
Stoicism Stoicism is an ancient Greek and Roman philosophy that treats virtue and rational judgment as the highest goods in human life.
Tulip Mania In 1630s Holland, prices for rare tulip bulbs soared to the cost of luxury homes before collapsing in history's first asset bubble.
US Dollar The US dollar is the official currency of the United States and the primary currency used in global trade and finance.
World War II World War II was a global conflict fought from 1939 to 1945 between two major alliances: the Allies and the Axis powers.
Zeno of Citium Zeno of Citium was a Hellenistic philosopher from Cyprus who founded the Stoic school of philosophy around 300 BC.