One of the principal forms of horse racing, which is popular in many parts of the world, is Thoroughbred racing. Harness racing is also popular in the eastern United States and more popular than Thoroughbred racing in Canada and parts of Europe. Quarter horse racing is also popular in the western United States and Florida. Racing with purebred Arabian horses exists in several states in the United States, as well as in most of Europe and the Middle East.

Monmouth Park (wikipedia)

A chariot race was said to be the event that founded the Olympic Games. According to one legend, mentioned by Pindar, King Oenomaus challenged his daughter Hippodamia's suitors to a race, but was defeated by Pelops, who founded the Games in honor of his victory. Today, we call this type of event harness racing. (wikipedia)