What is a Casino?
Casino is a modern term for an establishment that offers gambling-related entertainment. Slot machines, black jack, roulette, craps, and baccarat are the games that provide the billions of dollars in profits raked in by casinos each year. A smaller number of casinos are devoted to poker and other skill-based table games. In addition to the games themselves, many casinos offer complimentary goods and services (called comps) to their big spenders.
The earliest known casino was in the 16th century, in the city of Baden, Germany. This was part of a gaming craze that swept Europe at the time. Aristocratic visitors would gather at private clubs called ridotti to gamble and socialize with friends. 
Today, casinos are massive mega-entertainment complexes that have a variety of things to do beyond the gambling floor. They often include hotels, restaurants, non-gambling game rooms, bars and even swimming pools. Some have multiple floors and can house an astounding number of games.
Security is a major issue for casinos, since the amount of money that passes through them can make patrons and employees tempted to cheat or steal. This is why most casinos use cameras to monitor everything that happens inside. In addition, the patterns of gameplay and betting habits help to identify any suspicious behavior. Dealers are heavily trained to spot any blatant attempts to cheat, and the same goes for pit bosses and table managers. All of this helps to keep the casino safe and fair for everyone who visits.