Light behaves as both a particle and a wave simultaneously — this is called wave-particle duality.

Economist Arthur Laffer famously sketched the Laffer Curve on a napkin during a dinner meeting in the 1970s.

Genghis Khan killed so many people that it may have cooled Earth's climate by reducing agricultural CO₂ emissions.

Competitive sailing at the Olympic level involves reading wind shifts, currents, and opponents' tactics simultaneously.

At the 1904 St. Louis Olympics, the marathon was so chaotic that the first man to finish was disqualified for riding part of the way in a car.

Gagaku, Japan's imperial court music, is the world's oldest surviving orchestral tradition, dating to the 7th century.

The typewriter improved document production efficiency.

Extreme sports athlete Travis Pastrana became the first person to land a double backflip on a motorcycle at X Games 2006.

Traditional Japanese kabuki theater originally featured women actors — they were banned in 1629, and men have played female roles ever since.