A casino is a facility where people wager money on games of chance or skill. Some casinos offer table games like blackjack, roulette, and poker; others feature sports betting, and electronic gaming machines such as video poker. In addition to gambling, some casinos have restaurants and bars. The most famous casino in the world is probably the Casino de Monte Carlo in Monaco, built in 1863. Other notable casinos include the Bellagio in Las Vegas, Nevada; the Casino Baden-Baden in Germany; and Caesars Palace in Reno, Nevada.

The presence of large amounts of money in a casino makes it possible for both patrons and staff to be tempted to cheat or steal, either in collusion or independently. To prevent this, casinos use a variety of security measures. They may employ a physical security force to patrol the premises and respond to calls for assistance or reports of suspicious activity; or they may use specialized surveillance systems. In addition, most casinos give out complimentary items, called comps, to people who spend a lot of time and money gambling, such as free hotel rooms, meals, and tickets to shows.

In the past, organized crime figures supplied much of the cash used to operate casinos in Reno and Las Vegas. They were willing to invest in these enterprises despite their seamy reputation because they had lots of money from drug dealing, extortion, and other illegal rackets. As casinos grew more legitimate, they moved away from mob influence, and real estate investors and hotel chains bought up many of the old mafia-owned properties.