The world’s top casinos have something for everyone. From aquarium suites in Singapore to French casinos with dress codes in Monaco, you’ll find a casino that will suit your style. But no matter how fancy the casino, it all comes down to games of chance. Slot machines, blackjack, roulette, craps and baccarat bring in the billions of dollars in profits that keep casinos going.

Gambling probably existed before recorded history, with primitive protodice and carved six-sided dice being found in archaeological sites [Source: Schwartz]. But the modern casino as a place for people to play a variety of gambling games under one roof didn’t emerge until the 16th century. A craze for gambling swept Europe at that time, and Italian aristocrats gathered at private gambling houses called ridotti to play the games of their choice.

A casino’s security begins on the floor, where dealers and pit bosses keep an eye on patrons to make sure there are no blatant cheating tricks like palming or marking cards or switching dice. The eye-in-the-sky is also a crucial part of casino security, with cameras on the ceiling keeping tabs on every table and window and doorway.

Because all games of chance have an expected payout, it’s extremely rare for a casino to lose money for a day. Because of this virtual assurance of gross profit, casinos reward big bettors with comps such as free show tickets and hotel rooms, meals and reduced-fare transportation.