Prague Castle (Czech: Pražský hrad; [ˈpraʃskiː ˈɦrat]) is a castle complex in Prague, Czech Republic serving as the official residence and workplace of the president of the Czech Republic. Built in the 9th century, the castle has long served as the seat of power for kings of Bohemia, Holy Roman emperors, and presidents of Czechoslovakia. As such, the term "Prague Castle" or simply the "Castle" or "the Hrad" are often used as metonymy for the president and his staff and advisors. The Bohemian Crown Jewels are kept within a hidden room inside it. According to the Guinness Book of Records, Prague Castle is the largest ancient castle in the world, occupying an area of almost 70,000 square metres (750,000 square feet), at about 570 metres (1,870 feet) in length and an average of about 130 metres (430 feet) wide. The castle is among the most visited tourist attractions in Prague, attracting over 1.8 million visitors annually. Source: Wikipedia (en)