A casino is a building where people can gamble and play games of chance. Its glitzy facades, musical shows, fountains and shopping centers attract visitors from across the United States and around the world. But the billions of dollars in profits casinos rake in each year come from the gamblers themselves—from people betting on dice, slots, poker, blackjack, craps and more.

While the bright lights and giveaways lure visitors in, those with even a basic grip on math and economics can see that a casino’s real profits stem from gambling—a game at which almost everyone loses. This article will explore how casinos make money, the history behind them and some of their most famous sites (including the Bellagio in Las Vegas), what it’s like to gamble inside a casino, how casinos stay safe and the dark side of the business.

The first casinos grew out of horse racetracks and card rooms in the mid-nineteenth century. Then the state of Nevada legalized gambling in 1931, and the industry boomed. Casinos now are a major source of entertainment and tourism, and are found in cities as diverse as New York City and Seattle.

Despite the glamorous exteriors, casinos are rigged to bleed players of their cash. But there are ways to improve your odds of winning, or at least reduce the amount of money you give to a casino.