A casino is an establishment for certain types of gambling. These facilities are often combined with hotels, restaurants, retail shops, and/or cruise ships. The United States leads the world with the most casinos, followed by Romania, the Czech Republic, and Spain. Casinos vary widely in size and appearance, but most have gaming tables and slot machines. Some have live entertainment such as shows or concerts.

Gambling has been a part of human culture for millennia. Evidence of dice-based games dates back to 2300 BC in China, while card games appeared around 500 AD. Modern casino gaming began in the 19th century. Casinos became more popular in the United States in the 1980s, when state legislatures changed gambling laws to permit them. They also began appearing on Indian reservations, which were exempt from state antigambling laws.

Some casinos are very large, with multiple levels and thousands of slot machines. Others are much smaller, with only a few hundred slots or table games. Many of the larger casinos are situated in cities with high populations. Others are built in the mountains or on waterfront property. Some are open 24 hours, while others are closed during the night.

Some of the more famous casinos are known for their luxurious amenities, as well as their gaming options. These include the Bellagio in Las Vegas, the Monte Carlo in Monaco, and the Casino Baden-Baden in Germany. The casino in Baden-Baden, for example, first opened more than 150 years ago and originally attracted royalty and aristocracy from across Europe. It is still one of the most beautiful and elegant casinos in the world today.