Whether you hit the slots, put on your poker face or throw dice at the craps table, casinos are the place to scratch that gambling itch. And even though many casinos have hotels, restaurants, shopping centers, water parks, spas and non-gambling entertainment options, they would not exist without the billions of dollars in profits that come from games of chance like slot machines, blackjack, roulette, poker and baccarat.

Despite their seamy reputation, casinos are big business and have become more sophisticated than ever. The latest technology allows a casino to oversee the exact amount of money wagered minute by minute; computer systems can identify suspicious betting patterns; and “chip tracking” allows the casinos to monitor each patron’s actual bets.

While a large portion of a casino’s profits comes from the games, the owners also earn money by letting guests spend their winnings and comping them with free rooms, meals and shows. Those who play the most get the most benefits, including limo service and airline tickets.

While mobsters still provide much of the cash in Nevada’s casinos, legitimate investors have found that a casino business is a good way to make money. As the industry has expanded, so have the casinos, becoming larger and more luxurious. With bigger buffets, more games and top-notch hotels, they have become mini-amusement parks for adults. But the glitz and glamour mask a dark side: a major percentage of casino profits come from illegal activities.