A casino is a building or large room where people gamble. Its amenities include gambling devices such as roulette wheels, blackjack tables, poker tables, and slot machines, as well as entertainment such as theatre shows. In modern casinos, a wide range of technologies help oversee and control games. These include systems that record bets placed, electronic chips with built-in microcircuitry that allow them to be tracked minute by minute, and wheel and table designs that are electronically monitored for any statistical deviation from the expected outcome. In addition, some casinos hire mathematicians and computer programmers to work on the mathematical side of things.
In the United States, casinos are usually located in cities known for their tourism and are mainly operated by private companies. Many states have legalized casino gambling, and the number of casinos continues to grow. Some casinos are on American Indian reservations, which are exempt from state antigambling laws.
Casinos are carefully designed to influence how much people bet and to encourage them to play for longer periods of time. For example, some use a special low-tempo soundtrack that creates a relaxing effect and makes people feel more at ease with placing bets. Others use scents to promote their brand and cover unpleasant odors. Still others have catwalks in the ceiling above the gaming area that allow surveillance personnel to look directly down, through one-way glass, on the activities at the tables and slots. In these ways, the casinos hope to maximize the amount of money they can take in from gamblers.