A casino is a building or room where gambling games are played. Casinos are often combined with hotels, restaurants, retail shopping or cruise ships and are staffed by trained security personnel. In the United States, casinos are regulated by state laws and must be licensed to operate. Most states have passed laws to protect players from unscrupulous operators and ensure that the gambling revenues are used for their intended purpose.

A modern casino is like an indoor amusement park for adults, with lighted fountains, musical shows and themed rooms drawing in the crowds. But a casino would not exist without the billions of dollars that patrons wager each year on games of chance. Slot machines, blackjack, roulette, craps, baccarat and other games provide the entertainment that attracts people to gamble and provides the money that keeps casinos open.

Gambling almost certainly predates recorded history, with primitive proto-dice (cut knuckle bones) and carved six-sided dice appearing in the earliest archaeological sites. But the casino as a place where people could find a variety of ways to bet against each other did not appear until the 16th century. Italian aristocrats held private parties at places called ridotti during this time, and the popularity of these venues helped create the modern concept of the casino.

Given the large amounts of money handled within a casino, both patrons and employees may be tempted to cheat or steal, either in collusion or independently. To prevent this, casinos employ a variety of security measures, from surveillance cameras to rules of conduct.