Pianos have over 12,000 individual parts and are considered both string instruments and percussion instruments.

The development of artificial joints improved mobility.

The modern triathlon — swim, bike, run — was invented in California in 1974 as a way to settle debates about which sport produced the fittest athletes.

Usain Bolt's top recorded speed during his 100m world record was 44.72 km/h (27.8 mph).

The first modern Olympic Games in 1896 had only 241 athletes, all male, from 14 nations.

Cultural traditions are often passed down through generations.

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

People are more likely to comply with requests from authority figures.

Humans are unique in their capacity for cumulative culture — each generation builds on the last rather than starting over.