Project Blue Book officially ended in 1969.

Roman gladiatorial games were often less lethal than popular culture suggests — gladiators were expensive to train.

Reading a physical book before bed improves sleep quality more than reading on a screen.

The Large Hadron Collider is the world's largest particle accelerator.

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.

Usain Bolt holds the world record in the 100-meter sprint.

The world record for the 100m dash has dropped from 10.6 seconds in 1912 to 9.58 seconds today.

Project Blue Book investigated reports of unidentified flying objects.

The musical scale we use today was standardized at A = 440 Hz only in 1939 — different standards were common before then.