Horse-racing is a sporting activity which has been practiced over the centuries; the chariot races of Roman times were an early example, as was the contest of the steeds of the god Odin and the giant Hrungnir in Norse mythology. It is often inextricably associated with the activity of wagering on the outcome of a race, gambling.
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. Exceptional horses can win millions of dollars and make millions more by providing stud services, such as horse breeding.
The style of racing, the distances and the type of events varies very much by the country in which the race is occurring and many countries offer different types of horse-race.
In the United Kingdom for example, there are races which involve obstacles (either hurdles or fences) called steeplechase and those which are unobstructed races over a given distance (flat racing). See also United Kingdom horse-racing.
In the United States, races can occur on flat surfaces of either dirt or grass, generally Thoroughbred racing; certain tracks also offer Quarterhorse racing and harness racing. Racing with other breeds, such as Arabian horse racing, is found on a limited basis. The high point of US horse racing is the Kentucky Derby which, together with the Belmont Stakes and the Preakness Stakes, form the Triple Crown. Betting on horse racing is usually sanctioned and regulated by state governments through legalized parimutuel gambling.
Some of the world's most famous thoroughbred racehorses include:
The most famous horses from Canada are Northern Dancer, who after winning the Kentucky Derby and Preakness went on to become the most successful Thoroughbred sire ever, and his son Nijinsky II. In Canada, however, harness racing is more popular than Thoroughbred racing. Woodbine Race Track in Toronto, home of the Queen's Plate, Canada's premier stakes race, is the only race track in North America which stages Thoroughbred and Standardbred (harness) meetings on the same day.