A casino is a building that contains a gambling hall. People gamble at a variety of casino games, including poker, black jack, bingo, craps and roulette. The gambling industry is a billion-dollar business worldwide.

Gambling was illegal for much of America’s history, but it continued on clandestine lines, often with the complicity of local law enforcement officials. Nevada was the first state to legalize casino gambling, but it took decades before other states followed suit. Casinos compete to attract the most money from tourists, and they lure gamblers with free drinks, all-you-can-eat buffets and plush hotel rooms.

Every game a casino offers has a built in advantage for the house, but the edge can be very small. That slight edge earns the casino millions of bets, and it’s rare that a casino loses money in a single day. The profits help casinos fund elaborate hotels, fountains and giant pyramids, towers and replicas of famous landmarks.

Casinos also use a variety of psychological tricks to make their facilities more appealing to gamblers. Bright and sometimes gaudy colors are used on the floor and walls to create a stimulating and cheery atmosphere. Slot machines are designed to appeal to humans’ senses of sight, touch and sound—more than 15,000 miles (24,100 km) of neon tubing is used to light casinos in Las Vegas. Casinos are noisy places, with music blaring and staff shouting encouragement.

In 2005, Harrah’s Entertainment reported that the typical casino patron was a forty-six-year-old woman with above-average income who visited two or more casinos in the previous year. Those figures were based on face-to-face interviews with 2,000 adults and questionnaires mailed to 100,000.