A casino is a facility where gamblers can bet and play games of chance. In modern times, casinos are usually large building complexes with a variety of games and restaurants. They may also have bars, lounges, and other attractions to draw in tourists and locals alike. Most importantly, they have security personnel that ensures the safety of all guests. Usually, these security people are not armed but they do have the power to remove or threaten players from the casino if they do something illegal.

Most casino employees have a highly trained eye for cheating and other suspicious activity. Dealers are heavily focused on their own game and can easily spot blatant cheating such as palming, marking or switching cards or dice. Table managers and pit bosses have a broader view of the table and can quickly notice any unusual betting patterns. In addition, some casinos have catwalks in the ceiling that allow surveillance staff to look directly down, through one way glass, on the activities at the tables and slot machines.

In the beginning, casinos were the preserve of organized crime. Mob money helped them expand and renovate, and provided the cash needed to attract American tourists from across the country. However, legitimate businessmen soon realized the potential profits and began establishing their own casino operations. With federal crackdowns and the risk of losing a gambling license at even the slightest hint of mob involvement, casinos moved away from their seamy origins.