A casino is a gambling establishment where people can gamble and play games of chance. Most casinos offer a variety of games, including poker, blackjack, and roulette. Most games have mathematically determined odds that give the house an advantage over the players, which is known as the house edge. Casinos can be found in cities around the world and some countries have legalized them. In the United States, they are most prevalent in Nevada and Atlantic City. Some American Indian reservations also have casinos.

Modern casinos use a variety of technologies to monitor and regulate their operations. These include the use of video cameras to supervise gambling areas, and chip tracking devices that enable the casino to know exactly how much is being wagered minute-by-minute. Casinos are also using technology to ensure that the results of games such as roulette and craps are accurate.

Because of the large amounts of money handled within a casino, patrons and staff may be tempted to cheat or steal, either in collusion or independently. Many casinos have security measures to prevent this, and most have at least one person who is in charge of monitoring surveillance cameras and responding to calls for help or suspected criminal activity. Some casinos have catwalks in the ceiling that allow surveillance personnel to look down directly onto gaming tables and slot machines through one-way glass. Some casinos also have “hot spots” where surveillance personnel can watch the most active tables and slots.