A casino is a building where people can gamble and play games of chance. Its patrons may be tempted to cheat and steal, in collusion or independently. For this reason casinos have security measures to prevent such behavior. For example, a casino has security cameras that watch every table and window and can be focused on suspicious patrons by security workers in a room filled with monitors. Some casinos, especially those in Las Vegas and Atlantic City, are so heavily regulated that they can only operate with high levels of surveillance.

Casinos earn their money by giving out complimentary items or comps to gamblers (alcoholic drinks are usually available) and by taking a percentage of all bets made, or the “house edge,” as it is called in mathematics. The house edge varies between different casino games. Roulette, for example, attracts small bettors and has a lower house edge than craps. Craps, on the other hand, appeals to big bettors and has a higher house edge. Slot machines and video poker, which have a high-speed pay out rate, earn the most revenue for American casinos because they can be adjusted to yield a desired profit.

While gambling likely existed long before recorded history, the casino as a place for a wide variety of gaming under one roof developed in Europe during the 16th century with a popular gambling craze. It was not until the 1950s that organized crime figures found a way to make casinos a profitable enterprise by providing large amounts of capital and taking sole or partial ownership of the casinos.