A casino is a place where people can gamble, and it usually has a variety of different gambling games. It also has restaurants, hotels, non-gambling game rooms, and other amenities for patrons to enjoy. Some casinos have a very lavish design and atmosphere, while others are more low-key.

Casinos were originally small clubs for Italian aristocrats, called ridotti [Source: Schwartz]. The modern casino first appeared in Europe during the 16th century. As a gambling craze spread, people wanted to find a single location where they could gamble in a variety of ways. Casinos were developed to meet this need. They usually accepted a large number of bets and were guaranteed to make a certain amount of gross profit.

While musical shows, lighted fountains, shopping centers and elaborate themes help draw in the crowds, the casino business really revolves around gambling. Slot machines, blackjack, roulette, craps, baccarat and other table and card games generate the billions of dollars in profits that casinos pull in every year.

The elegant spa town of Baden-Baden in Germany was a playground for royalty and aristocrats 150 years ago, but now it attracts a much more diverse group of tourists, including celebrities, athletes, and regular gamblers. Its casino is one of the most beautiful on this list, and its red-and-gold poker rooms are modeled after the palace at Versailles. This is the only casino on the list that offers an on-site hotel. It is not the biggest casino in the world, but it is certainly one of the most famous and most popular.