A casino is a place where people can gamble and play games of chance. Many casinos have been built on Indian reservations, which are exempt from state antigambling laws. During the 1980s, casinos also began appearing in Atlantic City and on riverboats. There are now more than 3,000 legal casinos worldwide.

Although musical shows, lighted fountains and elaborate hotels draw in the crowds, most of a casino’s revenue comes from gambling. Slot machines, blackjack, roulette, baccarat and craps are the games that give casinos their billions of dollars in annual profits. In most cases, the house has a mathematical advantage over the players, which is usually less than two percent. This advantage is often called the house edge or vig, and it can vary from game to game.

In addition to their games, casinos focus on customer service and perks for high rollers. They offer complimentary items, or comps, and give free show tickets and food to certain patrons. They may also offer discounted hotel rooms and other services to encourage visitors. These efforts have helped casinos draw large numbers of tourists to Las Vegas and other gambling meccas. But many economic studies have shown that casinos shift spending away from other forms of local entertainment and that the costs of treating compulsive gamblers and lost productivity offset any financial gains they may bring to a community.

Casino security is largely divided between a physical force that patrols the floor and a specialized department that operates the casino’s closed circuit television system, which is sometimes nicknamed “the eye in the sky.” The surveillance system can be adjusted to focus on specific patrons, and it allows casino employees to instantly view the results of any suspicious betting activity or other anomalies.