Horse racing is an equestrian sport that has been practiced over the centuries. The chariot races of Roman times are an early example, as is the contest of the steeds of the god Odin and the giant Hrungnir in Norse mythology. The common sobriquet for Thoroughbred horse racing is The Sport of Kings.
In 1665, the first racetrack was constructed on Long Island. The American Stud Book was started in 1868, which prompted the beginning of organized horse racing. There were 314 tracks operating in the United States by 1890 and in 1894, the American Jockey Club was formed.
Horse racing flourished until World War II. The sport did not regain popularity until horses began to win the Triple Crown -- a series of three races, consisting of the Kentucky Derby, the Preakness, and the Belmont Stakes.
One of the principal forms of horse racing, which is popular in many parts of the world, is Thoroughbred racing. Harness racing for Standardbred horses is also popular in Australia, New Zealand, the eastern United States and more popular than Thoroughbred racing in Canada and parts of Europe. Thoroughbred racing is done on the flat or over jumps, as steeplechasing or hurdles races.
The different types of racing all concern different breeds of horses. The Thoroughbred races moderate distances at very fast paces. The Standardbred horses use their ability to race in harness at a trot or pace instead of under saddle at a gallop.
The breeding, training and racing of horses in many countries is now a significant economic activity as, to a greater extent, is the gambling industry which is largely supported by it. The time invested in training these horses is extensive and varies according to the type of race the horse is involved in. Exceptional horses can win millions of dollars and might make millions more by providing stud services, such as horse breeding.
Thoroughbred racing has two main associations, National Thoroughbred Racing Association and Thoroughbed Owners and Breeders Association. The association for harness racing is United States Trotting Association.