A casino is a place where people gamble and play games of chance. Casinos generate most of their revenue from patrons placing bets on games of chance, but some offer skill-based games such as craps, roulette, baccarat, and blackjack. Most casino games have a built-in house edge, which can be lower than two percent, but over the millions of bets placed each year, it adds up.

To offset the house edge, casinos spend a lot of money on security. In addition to the traditional armed guards, many now employ high-tech surveillance systems. Cameras in the ceiling monitor every table, window, and doorway and can be directed to focus on suspicious patrons. Electronic systems in the tables allow casinos to track betting patterns minute by minute and to detect any deviation from expected results.

In an effort to lure gamblers, most casinos offer perks that make gambling more affordable. In the 1970s, Las Vegas casinos marketed heavily discounted travel packages and free hotel rooms to encourage gambling, even for locals. In the 21st century, a casino might feature a $5 blackjack table and a 24-hour cafe that serves free coffee and cigarettes.

Although legitimate businessmen were reluctant to invest in casinos because of their seamy association with organized crime, mobster families poured cash into Reno and Las Vegas. They took sole or partial ownership of several casinos and used their influence to manipulate game outcomes. Some mobsters even became involved in the management of some casinos, creating a culture of corruption that left an indelible mark on gambling.