In the 11th century, clean drinking water in Europe was hard to come by, and waterborne diseases were common. Arnold of Oudenburg, a former soldier turned Benedictine abbot in present-day Belgium, took an unusual approach to protecting his community.

For decades, the leading theory held that the first Americans arrived in a single migratory wave from Eurasia across the Bering land bridge over 15,000 years ago.

In 1665, Dutch scientist Christiaan Huygens lay sick in bed, watching two pendulum clocks he had built swing from a beam above him.

Perched on a hill in Halifax, West Yorkshire, Wainhouse Tower rises 275 feet (84 meters) into the sky. Though it looks like a grand Victorian monument, it began as something more practical: a chimney.

In 1882, on the cliffs of Posillipo, Italy, locals watched in confusion as a Frenchman aimed a strange device at birds and pulled the trigger. But no feathers flew.

On April 26, 1986, a reactor at the Chernobyl Nuclear Power Plant exploded, creating one of the most devastating nuclear disasters in history.

Stephen Burroughs was born in 1765 in Connecticut and raised in Hanover, New Hampshire, where he quickly earned a reputation as the worst boy in town.

In Budapest’s 10th district, beneath the streets of Kőbánya, lies a vast network of tunnels that once supplied limestone for Hungary’s most iconic buildings.

On September 23, 1999, NASA’s Mars Climate Orbiter vanished without a trace. The spacecraft, designed to study the Martian atmosphere and relay communications for a lander mission, had completed a 9.5-month journey across 669 million kilometers.

Long before bacteria were linked to tooth decay, civilizations across the globe blamed a sinister culprit: the tooth worm.