A casino is a place where people can gamble and win or lose money. It is a popular tourist attraction and some casinos are designed to look like castles or palaces. The most famous casino in the world is in Monte Carlo, Monaco. Other well-known casinos are in Las Vegas and Atlantic City. In recent years many new casinos have opened in other cities and countries. Some are small, but others are huge and impressive. These casinos often have five-star hotel accommodations, Michelin star restaurants and designer shops. They also offer top-billed entertainment shows.

A modern casino has a large number of security measures. These include physical security guards and a specialized surveillance department. These departments work closely together to monitor all activities in the casino and respond quickly to any reports of suspicious or definite criminal activity. Casinos also have catwalks in the ceiling above the gambling floor, which allow surveillance personnel to look directly down, through one-way glass, on activities at tables and slot machines. Computers and video cameras also routinely supervise the games themselves. For example, chip tracking enables the casinos to oversee precisely the amounts wagered minute by minute and alert them to any anomaly; and roulette wheels are electronically monitored to discover statistical deviations from expected results as soon as they occur.

A number of states in the United States have changed their laws during the 1980s to permit casinos. Some of these casinos are built on American Indian reservations and are not subject to state anti-gambling statutes.