A casino is a place where gambling activities take place. Regardless of the extras (like restaurants, free drinks, stage shows and dramatic scenery) that help lure gamblers in, casinos would not exist without games of chance like poker, blackjack, roulette, craps, baccarat, slot machines and more. These games generate the billions in profits that casinos rake in every year.
Something about casinos seems to encourage people to cheat or scam their way into a jackpot, which is why they spend such a large amount of time, money and effort on security. The routines of the games themselves also follow certain patterns, which makes it easier for security people to spot anything that deviates from the norm. For instance, the way dealers shuffle and deal cards or the expected reactions and motions of players following a game all fall into specific patterns that can be easily picked up on by trained security people.
The largest casino in the world is in Macau, a city-state that has been legally permitted to operate casinos since 2002. In the United States, most casinos are located in Nevada. The legal status of casinos in other states varies from state to state. Casinos that are open to all residents of a state have an advantage over those that cater specifically to tourists.