A horse race is a competition between horses, usually on a flat surface, over a distance of a quarter mile or more. The race may be a sprint or a long-distance test of stamina. Spectators often wear elegant clothing and sip mint juleps while watching the race, but behind the glamour is a world of injuries, drug abuse, and slaughter.

In medieval England, professional riders, known as jockeys, demonstrated the speed of their mounts to potential buyers by racing them. They were paid a fee to race the horses, and their earnings depended on how well they did. After a time, many nobles and aristocrats took up the sport themselves. During the reign of Louis XIV (1643-1715) and later in France, gambling on horse races became legal.

When the sport moved from the countryside to city courses, prize money increased. Spectators began to dress in elaborate costumes, and racecourses became grand spectacles. Prizes such as a gold watch or a silver cup encouraged owners and jockeys to strive for the best performance. The sport also developed a reputation for class, with races restricted to certain types of horses and held on the most prestigious tracks.

Modern horse races are regulated by state and national laws that require horse owners to register their horses, hold a license to operate a racetrack, and submit to regular drug tests. The sport is overseen by a national body called the Horseracing Integrity and Safety Authority, which has come under criticism for allowing the use of sedatives in training and a cocktail of drugs that mask injuries and enhance performance.

Some people have become disillusioned with the romanticized image of horse racing, especially when it is accompanied by reports of drug abuse and gruesome breakdowns. Some critics call for a total ban on the sport, while others endorse reforms such as a zero-tolerance drug policy, turf (grass) tracks only, a ban on whipping, and competitive racing only after horses have reached their third birthdays.

One of the most infamous horse races in the world is the Palio di Siena, which takes place twice a year on July 2 and August 16 in the city of Siena, Italy. The race pits the seventeen Contrade, or city wards, against each other in a pageant that attracts tourists from around the world. Spectators cheer for their chosen team and watch the spirited, prancing horses run in front of medieval towers and historic buildings.