A casino is a place where people can gamble, primarily using games of chance. Although gambling has existed almost as long as recorded history (primitive protodice and carved six-sided dice are found in archaeological sites), the modern casino, offering a variety of ways to win money under one roof, was developed during a gambling craze in Europe in the 16th century. Today, casinos are found around the world. The majority of casinos are located in the United States, with the Las Vegas Valley having the highest concentration. Casinos are also found on American Indian reservations and in some other countries, such as the Philippines.
Because of the large amounts of money involved, casinos must take care to prevent cheating and theft by patrons and employees. Security measures include cameras and, in some cases, computerized surveillance systems. For example, chip tracking allows a casino to monitor the exact amount of money wagered minute-by-minute and to be warned immediately of any anomaly; and roulette wheels are regularly monitored electronically for statistical deviations from expected results.
Many casinos offer a wide variety of games, from the most common, such as slot machines and blackjack, to regional variations on those themes. In the United States, these games include craps, keno and roulette. Many American casinos also feature sports bookmakers, which accept bets on various events. Moreover, some casinos cater to high rollers, giving them special rooms and lavish personal attention. These high rollers also enjoy extravagant comps, such as free or discounted shows and hotel rooms.