History

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

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.
Epictetus Epictetus was a Greek Stoic philosopher who taught that suffering comes from trying to control external events rather than our own actions.
Flying buttress How external arched flyers redirected heavy vault forces to massive outer piers, creating space for Gothic stained-glass windows.
Gaius Musonius Rufus Gaius Musonius Rufus was a 1st-century Roman Stoic philosopher who taught Epictetus and advocated equal philosophical education for women.
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.
Meditations Marcus Aurelius wrote Meditations as a private journal of Stoic reflections while running the Roman Empire and leading military campaigns.
Notre Dame Cathedral Notre Dame Cathedral is a medieval Catholic cathedral and basilica located on the Île de la Cité in Paris, France.
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.
Seneca the Younger Seneca the Younger was a Roman Stoic philosopher, dramatist, and imperial advisor who managed Emperor Nero while writing major moral texts.
Zeno of Citium Zeno of Citium was a Hellenistic philosopher from Cyprus who founded the Stoic school of philosophy around 300 BC.