The history of Prague begins with its Castle, founded by Prince Bořivoj in the 9th century. Situated high above the Vltava River, the buildings enclosed by the Castle include a palace, a monastery and three churches. A town called Hradčany in part of the Castle's outer wall. Over the centuries, the Castle has been rebuilt numerous times. After a fire in 1541, many damaged buildings were reconstructed in Renaissance style. Since 1918, the Castle has been the seat of the current president of the Czech Republic. Changing of the Guard takes place every hour with the noon ceremony being most elaborate. According to the Guinness Book of World Records, the Prague Castle is the largest coherent castle complex in the world, with an area of almost 70,000 square meters. Prague Castle is the most popular sight visited in Prague. It is the largest ancient castle in the world being 570 meters long, on average 128 meters wide covering an area of 7.28 hectares.