The harmonica is the world's best-selling musical instrument.

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

The Olympic rings represent the five continents of the world — but no particular ring is tied to a specific continent.

Cultural traditions are often passed down through generations.

The longest recorded rally in professional tennis lasted 643 shots in a match in 1984.

Particles can exist in multiple states until observed.

The first woman to complete the Boston Marathon officially was Kathrine Switzer in 1967, despite officials trying to pull her off the course.

The first modern Olympic Games were held in Athens in 1896 with 14 nations participating.

The original purpose of ballet was entertainment for the French royal court, not performance art.