A casino, also known as a gambling house or a gaming house, is an establishment for certain types of gambling. Most casinos feature multiple games of chance and some involve skill. Some are integrated with hotels, restaurants, retail shops or cruise ships. In the United States, there are more than 30 states that have legalized casinos. Most of these are located in Nevada, which has the most popular ones, and are often situated on or near rivers, lakes or mountains. A few are located on American Indian reservations, which are not subject to state laws regulating gambling.

Casinos are designed to make money for their owners. Every game has a built in mathematical advantage for the casino, and these gains, which are usually no more than two percent, can add up quickly. This money allows the casino to cover a large percentage of its operating costs, including the payments to winning players.

The concept of the casino developed in the 16th century during a gambling craze that swept Europe, with Italian nobles meeting in private rooms called ridotti to gamble and socialize [Source: Schwartz]. These venues were not technically legal, but they avoided the attention of the Inquisition by keeping their gambling activities hidden from outsiders.

The casinos of today are equipped with a variety of technological surveillance systems and security measures to prevent cheating, theft and other criminal acts. Casino employees monitor patrons closely and are trained to recognize specific movements or betting patterns that might indicate a potential crime is being committed. In addition, some casinos have catwalks above the casino floor that allow security personnel to look down through one-way glass at all tables, slots and windows.