A horse race is a sport whereby horses are ridden in competitive events, most commonly over flat races on grass or dirt. The horses are forced to run a set distance within a set timeframe, usually in an enclosed facility such as a stadium or a track. The winner is determined by the first horse across the finish line.

One of the oldest sports in history, horse racing has evolved from a primitive contest of speed or stamina to a modern spectacle involving huge fields of runners and sophisticated electronic monitoring equipment. Its basic concept, however, has remained unchanged over centuries, and winning a horse race is still a matter of putting the fastest or most durable animal in the lead at the end of the race.

The sport was a popular pastime among the ancients, and archeological records indicate that horse races took place in Greece, Rome, Babylon, Syria, and Egypt. It was also an important part of myth and legend, such as the contest between the god Odin and his steed Hrungnir in Norse mythology. Today, horse races are a global phenomenon.

There are a number of different types of horse races, but the most common are the allowance and claiming races. The former are open to any horses that meet minimum age requirements and have a certain amount of experience. The latter are races that have a lower limit on the price a trainer can pay to enter a horse. These races attract a mix of young, inexperienced horses looking to make a name for themselves and older salty veterans that have won a lot of races.

Some of the most famous horse races are the Triple Crown races, which are limited to three-year-old thoroughbreds. These races, along with the Preakness Stakes and Belmont Stakes, are considered to be some of the biggest and most prestigious horse racing events in the world.

Other major horse races include the Prix de l’Arc de Triomphe, which is held in Paris and offers some of the largest purses in the sport. It is a long-distance race over two or more turns and tests the endurance of horses as well as their speed.

In addition to the size of the prize money, some horse races are restricted by age, sex, and location, or have other conditions that must be met in order for a horse to compete. For example, some races require a certain type of pedigree, while others are restricted to a specific breed or gender. Depending on the circumstances, a horse may need to compete in more than one race to be eligible for the top prizes. It is a complicated process, and even the best-laid plans can fall apart. The most successful horses are those that can adapt to the changing conditions.