Polo is a fast-paced sport where players on horseback use long mallets to hit a small ball into the opposing team's goal. Think of it like hockey, except the players ride horses and the playing field is very large.

The game originated in ancient Persia (modern-day Iran) over 2,000 years ago, where it was used to train cavalry troops. British soldiers stationed in India learned the game in the 1800s and brought it back to England, where it became popular among the wealthy. Today, polo is played in countries around the world, from Argentina to the United States.

Each team has four players, and the horses (called polo ponies, even though they're full-sized horses) are just as important as the riders. A good polo pony needs to be quick, agile, and smart enough to anticipate where the ball is going. Players often switch horses between the six periods of play, called chukkers, because the sport demands so much from the animals.

The word polo also appears in “water polo,” a completely different sport played in swimming pools. It also shows up in the name “Marco Polo,” the famous 13th-century Italian traveler who went to China.