The modern casino is like an indoor amusement park for adults, but most of the entertainment — and the profits for its owners — comes from gambling. While musical shows, lighted fountains and shopping centers help draw in the crowds, casinos would not exist without games of chance such as slot machines, roulette, craps, poker, blackjack and keno. These games of chance, along with the countless other card and table games, account for the billions in annual profits that casinos rake in.

Casinos make money by offering a built in statistical advantage, called the house edge, on almost every game they offer. That advantage can be as low as two percent, but it adds up over the millions of bets placed by casino patrons each year. This profit, called the vig or rake, is how casinos turn gambling into a multibillion-dollar business.

Most Americans are familiar with the glamorous images of tuxedo-clad gamblers at high stakes tables in a casino’s high roller room. But many people don’t know how casinos began and what they’re really about.

Until the 1950s, gambling was illegal nationwide. Even after Nevada legalized it in 1931, the growth of casinos outside the state was stifled for decades. But organized crime figures had lots of money from their drug dealing and extortion rackets, and they saw the potential for casinos as a way to bring in cash and attract tourists. These gangsters funded the early Las Vegas casinos and became involved in their operation, often taking sole or partial ownership of them.