From the glittering lights of Las Vegas to the illegal pai gow parlors in New York’s Chinatown, casinos are places where people can gamble on games of chance. Despite the fact that many casinos offer shopping, restaurants and elaborate stage shows, the vast majority of their profits are derived from gambling. Slot machines, blackjack, roulette and craps generate the billions of dollars in profits that casino owners rake in every year.

The modern casino is a giant entertainment complex, complete with theaters, multiple gaming floors and elaborate lighting. But it would not exist without the games themselves. While gambling on games of chance predates recorded history, the first government-sanctioned gambling house was the Ridotto in Venice in 1638. During the time of the Italian Republic, this four-story building had rooms for primitive card games and offered food and drink to its patrons.

In addition to a variety of game offerings, most casinos offer a comp program that rewards loyal gamblers with free goods and services. Players earn points based on their total amount of play that can be redeemed for discounted or free hotel rooms, meals, show tickets and even airline tickets. Casinos also keep a close eye on their patrons through sophisticated surveillance systems. Cameras mounted in the ceiling can be manipulated to focus on specific suspicious patrons, and security personnel watch over tables and slot machines through a series of one-way mirrors. These mirrors can be adjusted to zoom in on the action and catch anyone trying to cheat.