A casino is a room or building where people can gamble and play games of chance. It is a popular pastime and the gambling industry has grown to be a large part of many cities’ economies. People from all walks of life visit casinos to gamble and spend time with friends. Many casinos are elaborate, combining hotels, restaurants and entertainment venues with gaming areas. Some are even designed as landmarks, such as the Empire at Leicester Square in London or the Venetian Macao in the Cotai Strip in China.

In the United States, casinos began appearing on American Indian reservations, which are not subject to state antigambling laws. In the 1980s, casinos also began opening in Atlantic City and on various cruise ships. Today, there are more than 3,000 legal casinos worldwide. Casinos earn money by charging a small percentage of each bet to players. This is known as the house edge and it can vary from game to game. The average casino has a house edge of two percent or less.

Casinos often use security measures to prevent cheating and theft. In addition to cameras, they employ dealers who are trained to spot a wide variety of techniques that could indicate a player is cheating. They also watch patrons’ betting patterns closely and look for signs that someone is stealing chips. Casinos also prohibit the wearing of bright, gaudy clothing, which can be mistaken for gambling money and may alert security personnel to suspicious activity.