Casino is a place where people can gamble. While musical shows, lighted fountains, shopping centers and elaborate hotels may draw the crowds, casinos would not exist without games of chance like blackjack, roulette, craps and slot machines that earn them billions in profits every year.

The built in advantage of each game gives the house a virtual assurance of gross profit, even over a long period of time. This is known as the house edge and it can be very low, such as in the case of roulette (with a double zero), or quite high, as in the case of Craps.

Because of this, casino security is a major focus in the industry. Staff keep a watchful eye on the patrons to spot any suspicious activity or collusion; table managers and pit bosses have a broader view and are able to see betting patterns that may signal cheating. Casinos are also increasingly deploying technology to monitor and control their games. For example, roulette wheels have built in microcircuitry that allows them to be scanned minute-by-minute for any statistical deviation from their expected results.

While mobsters ran the first casinos, the real estate developers and hotel chains that grew wealthy from them eventually bought out the mob. Then they expanded the casinos, opening them up to more than just Las Vegas and Atlantic City; a number of American states amended their laws in the 1980s to permit casino gambling. Today, casinos are found throughout the world.