Casinos make their money by offering a variety of gambling games. Unlike your grandmother’s weekend bus trips to the local casino, today’s casinos are huge resorts that house a mind-boggling number of games and activities. They feature a wide range of amenities that attract gamblers and non-gamblers alike, such as restaurants, hotels, theaters and even non-gambling gaming rooms like bars and sports books.

While casinos do rely on music, shopping centers, lavish hotels and other attractions to draw in crowds, their primary source of income is the billions of dollars that patrons wager. Casinos make their profits by taking a built in statistical advantage of a game’s odds and adjusting the payouts accordingly. The edge can be very small, as low as two percent in some cases, but it adds up over time.

The modern casino may look much like an indoor amusement park for adults, with lighted fountains and replicas of famous landmarks, but it would not exist without games of chance. Slot machines and table games like blackjack, roulette, craps and baccarat provide the billions of dollars in profits that casinos generate every year.

Gambling almost certainly predates modern civilization, with primitive protodice (cut knuckle bones) and carved six-sided dice discovered in ancient archaeological sites [Source: Schwartz]. But the casino as a gathering place for a multitude of gambling activities did not develop until the 16th century during a craze that saw European royalty and the aristocracy gather in exclusive spaces called ridotti.