A horse race is a competitive sport in which riders mount horses and attempt to lead them around an established course, usually over obstacles (or hurdles, if present). The winners receive a prize, depending on the specific race. Horse racing is a popular sport, and it has been practiced in civilizations throughout the world since ancient times. The modern form of the sport dates back to the mid-18th century, when Thoroughbred breeders developed standardized races for different age groups and sexes.

During the 19th and 20th centuries, the most prestigious and demanding races were created, along with rules for eligibility based on age, sex, race history, birthplace, and training methods. Some races are restricted to a single racehorse, while others are open to all, but are weighted for fairness. These races are called handicaps and allow for a wide range of performance factors to be taken into account, including the previous performances of each horse.

In modern times, horse racing has become a multibillion-dollar industry with an enormous global following. While most people watch the events on television, many also attend the races in person to see for themselves. There are more than 1,000 races held in the United States every year, and they attract millions of spectators. In addition, millions of dollars are invested by private owners in training and maintaining their horses.

Despite the romanticized image of horse racing as an event in which spectators don fine clothes and sip mint julips, the reality behind the scenes is often brutal. The animals used in the sport are forced to run at such high speeds that they frequently sustain serious injuries, including heart failure and pulmonary hemorrhage (bleeding out of the lungs). Many horses die after an accident on the track, either from head trauma or from broken legs.

The most prestigious and demanding races are the Classics, which include the Kentucky Derby, Preakness Stakes, and Belmont Stakes in the United States. These three races make up the Triple Crown, a feat that has only been accomplished three times in the entire history of the sport. Other great races are the Prix de l’Arc de Triomphe in France and the Dubai World Cup in the United Arab Emirates.