A casino is a building where people can gamble and play games of chance. The games played vary by location, but many casinos specialize in certain games. Casinos are also used for entertainment purposes, such as live music and dancing. Some also serve food and drinks. Casinos can be found worldwide, but the majority are located in the United States. In 2002 over 51 million people visited casinos in the United States.

The earliest casinos were run by the mob. However, mob control was eventually lost to real estate investors and hotel chains that realized how profitable casinos could be. These companies bought out the mobsters and began running casinos without mob interference.

In order to maximize profits, casinos are designed to be visually appealing and acoustically pleasing. Bright and sometimes gaudy colors are used to create a cheerful atmosphere. Red is especially popular, because it has been shown to make people lose track of time. There are also no clocks on the walls of a casino because people tend to ignore them while gambling.

Casinos are designed to attract gamblers and keep them playing, even if they are losing money. They use a variety of techniques to do this, including the arrangement of gambling machines and tables in a maze-like fashion that makes it hard for patrons to leave. They also use acoustic signals to encourage the players to stay, and more than 15,000 miles of neon tubing is used to light them.