A casino is a place where people play gambling games. It has a large variety of casino games and often also offers other entertainment like shows and restaurants. In the United States, casinos are located mostly in Las Vegas and Atlantic City. Some are on American Indian reservations and are not subject to state antigambling laws.
Casinos make their money by taking a percentage of bets made by gamblers. This percentage can be small (lower than two percent) but over time it adds up to billions in profits for the owners of the casino. Most of these profits are made from games with an element of chance but some, such as blackjack and roulette, have a small skill component. In these games, the house has a built in advantage over players, which can be described mathematically as the expected value of a bet.
Because casinos handle a lot of money, they have to take precautions against theft by either patrons or staff. Security cameras are frequently used to monitor activity. In addition, most casinos do not have clocks on the walls because they are thought to distract customers from keeping track of time. Casinos are often decorated with bright, sometimes gaudy colors such as red to stimulate customers and keep them awake.
While gambling likely existed as early as recorded history — primitive protodice and carved knuckle bones have been found at archaeological sites — the casino as we know it did not appear until the 16th century, when a gambling craze swept Europe. The first casinos were private clubs for the elite, known as ridotti.