For thousands of years, horse racing flourished as the sport of kings and the nobility. Modern racing, however, exists primarily because it is a major venue for legalized gambling.
Horse racing is the second most widely attended U.S. spectator sport, after baseball.
Horse racing is also a major professional sport in Canada, Great Britain, Ireland, Western Europe, Australia, New Zealand, South Africa, and South America. By the time humans began to keep written records, horse racing was an organized sport in all major civilizations from Central Asia to the Mediterranean. Both chariot and mounted horse racing were events in the ancient Greek Olympics by 638 BC, and the sport became a public obsession in the Roman Empire. The origins of modern racing lie in the 12th century, when English knights returned from the Crusades with swift Arab horses. Over the next 400 years, an increasing number of Arab stallions were imported and bred to English mares to produce horses that combined speed and endurance.