A casino is a place where people gamble on games of chance. It may also include dining, drinking and entertainment. The most famous casinos are in Las Vegas, but there are many others around the world. Some of them are very lavish, with a lot of expensive decorations, stage shows and other amenities.
Some casinos are heavily guarded to protect patrons and staff from theft and cheating. This is especially important because casinos deal in large amounts of money and are a prime target for crime. There are a variety of security measures, from physical security forces to cameras that monitor the gaming area and the surrounding buildings. A number of these systems are automated; for example, betting chips have built-in microcircuitry to enable them to be overseen minute-by-minute by computers and alerted if there is an anomaly; and roulette wheels are regularly electronically monitored for any statistical deviation from their expected results.
Something about gambling (maybe the opulent surroundings and the presence of large sums of money) seems to encourage people to try to cheat or steal, either in collusion with other players or independently. This has led to casinos spending a lot of time, effort and money on security.