From the glittering lights of Las Vegas and Monte Carlo to the raucous gambling halls in New York’s Chinatown, about 51 million people – a quarter of all Americans over the age of 21 – visited casinos last year. And worldwide the number is even higher.

Whether playing craps, blackjack, roulette or poker, all casino games have some element of skill involved. That’s why many of these establishments feature a high staff to player ratio. In some American casinos, for example, the ratio is 1 to 4.

The game selection varies widely as well. In Europe, roulette is a staple, especially at those casinos frequented by the British, while in America blackjack and poker are the most popular table games. Asian casinos rely more on traditional Far Eastern games, including sic bo, fan-tan and pai gow.

Something about the large amount of money at stake seems to encourage cheating and stealing by patrons. So casinos devote a great deal of time and effort to security measures. For instance, table managers and pit bosses oversee each game with a view to spotting patterns of betting that might signal tampering. And the games themselves are often closely monitored through video cameras.

In the 1990s, casinos also dramatically increased their use of technology to monitor and control their games. For instance, betting chips have built-in microcircuitry that allows a casino to keep track of how much is wagered minute by minute and detect any deviation from expected results.