A casino is a building that houses gambling games. The precise origin of gambling is unknown, but it has long been a popular leisure activity. Modern casinos are often large entertainment complexes with hotels, restaurants and non-gambling games. They are also designed to be beautiful, exciting and awe-inspiring. They feature multiple levels, exotic decor, high-tech lighting and mindblowing array of games.

The primary way casinos make money is by charging patrons to play their games of chance. Each game has a built in advantage for the casino, typically less than two percent, which when multiplied by the millions of bets placed each year by patrons earns the casinos huge profits. This money enables the casinos to build elaborate fountains, hotel suites, shopping centers and replicas of famous landmarks.

As the popularity of casinos grew, organized crime groups became heavily involved in the businesses. Mafia members supplied the funds, and in some cases took sole or partial ownership of the casinos. In the 1980s, American states began to legalize casinos, initially on riverboats and later in Atlantic City and on Indian reservations.

Modern casinos employ a wide variety of security measures to protect their guests and assets. A physical security force patrols the floor and responds to calls for assistance or alleged criminal activity. A specialized surveillance department operates the casino’s closed circuit television system, known as the eye in the sky. Other technological advances have helped casinos improve their security. For instance, the use of microcircuitry in betting chips allows casinos to oversee bets minute-by-minute and detect cheating; roulette wheels are electronically monitored regularly to discover any statistical deviations from normal operation.