A casino is a place where gambling takes place. Modern casinos are glamorous entertainment complexes with many luxuries, such as restaurants and free drinks, and offer gambling of various kinds, including table games like blackjack, roulette, craps, and poker, and slot machines. They also feature live shows and other forms of entertainment, such as musical performances or comedy acts.

Something about gambling (perhaps the presence of large amounts of money) seems to encourage people to cheat and steal, both in collusion with other patrons or independently; thus, casinos have a variety of security measures. These include cameras, and in some cases security personnel who watch the action from catwalks that extend over the casino floor, allowing them to view gamblers through one-way mirrors.

Although gambling almost certainly predates recorded history, the development of casinos as a centralized location for multiple types of gambling activities did not occur until the 16th century, when a gambling craze spread from Europe to America, and wealthy Europeans created private clubs known as ridotti. Although technically illegal, these clubs were rarely bothered by legal authorities.

Most casinos make their money by giving patrons a chance to win money, usually in exchange for chips that represent the real money they are risking. Most games of chance give the house a mathematical advantage, but some, such as blackjack and poker, offer a reduced house edge to attract larger bettors. Casinos also generate income from slots and video poker machines, which are programmed to accept bets of varying sizes at random.