A casino is a large room or building in which people can gamble. Casinos usually have many games that people can play, including slots, poker, blackjack, and roulette. They also often have other entertainment such as shows. Casinos can be found in Las Vegas, Atlantic City, and other places around the world.

Something about gambling (perhaps the huge amounts of money involved) seems to encourage cheating and theft. For this reason casinos spend a great deal of time and effort on security. Casino security starts on the casino floor, where employees keep an eye on patrons and games to prevent blatant cheating or collusion. They also use electronic monitoring to oversee the game results, checking for statistical anomalies. Casinos also have special rooms for high-roller gamblers. These rooms have private gambling areas where the high rollers can place bets in the tens of thousands of dollars. In addition to the special rooms, high-roller gamblers often receive other perks such as free spectacular entertainment and luxurious living quarters.

Gambling likely predates recorded history, with primitive protodice (cut knuckle bones) and carved six-sided dice appearing in archaeological sites. However, the casino as a place where people could find a variety of ways to gamble under one roof did not develop until the 16th century, when a gambling craze swept Europe. During the 1980s and 1990s, casinos began to appear on American Indian reservations. This allowed them to operate legally in states that had previously enacted anti-gambling laws.