The fastest recorded tennis serve exceeded 150 miles per hour.

The Olympic flame tradition was revived at the 1928 Amsterdam Games; the torch relay began at the 1936 Berlin Olympics.

The development of artificial joints improved mobility.

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

Particles can exist in multiple states until observed.

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

Synchronized swimming, now called artistic swimming, requires athletes to hold their breath for up to 3 minutes while performing choreography.

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

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