Karlovy Vary is a spa city in the Karlovy Vary Region of the Czech Republic. It has about 48,000 inhabitants. It lies on the confluence of the rivers Ohre and Teplá, approximately 130 km (81 mi) west of Prague. It is named after Charles IV, Holy Roman Emperor and the King of Bohemia, who founded the city in 1370. It is the site of numerous hot springs (13 main springs, about 300 smaller springs, and the warm-water Teplá River), and is the most visited spa town in the Czech Republic. Until 1945, when the German-speaking inhabitants were expelled, the city was overwhelmingly German-speaking.

In the 19th century, Karlovy Vary became a popular tourist destination, especially known for international celebrities who visited for spa treatment. The city is also known for the Karlovy Vary International Film Festival, which is one of the oldest in the world and one of Europe's major film events.

The city has been used as the location for a number of film-shoots, including the 2006 films Last Holiday and box-office hit Casino Royale, both of which used the city's Grandhotel Pupp in different guises. Moreover, the Palace Bristol Hotel in Karlovy Vary had been used as a model for The Grand Budapest Hotel movie.