Casinos are gambling establishments that offer a wide variety of games of chance and in some cases skill. The games range from the very simple, like keno and bingo to the very complex, such as blackjack and roulette. In many countries, casinos are licensed and regulated by government authorities. The casinos are also a major source of revenue for local communities.

Because of the large amount of money involved, security in a casino is paramount. Casinos employ a variety of methods to keep their patrons safe. Some of these methods are technological, such as cameras monitoring the casino floor; others involve more hands-on measures, such as requiring players to keep their cards visible at all times. Casinos also monitor their operations through electronic systems, such as chip tracking (which enables the casino to supervise betting chips minute-by-minute) and electronic roulette wheels that are monitored regularly for statistical deviations from expected results.

In the twentieth century, casinos increasingly specialized in high-stakes games. These games were usually played in special rooms away from the main casino floor, and the maximum bets could reach tens of thousands of dollars. The casinos made much of their profits from these gamblers, and they encouraged them to play by offering free spectacular entertainment, luxurious living quarters, reduced-fare transportation, and other inducements. As a result, the mob began to lose control of some casinos; and real estate developers and hotel chains purchased and ran them. The casino industry then grew rapidly in the United States and abroad.