Hohenzollern Castle is the ancestral seat of the imperial House of Hohenzollern.] The third of three castles on the site, it is located atop Berg Hohenzollern, a 234 m bluff rising above the towns of Hechingen and Bisingen in the foothills of the Swabian Alps of central Baden-Württemberg, Germany.A popular tourist destination, Hohenzollern castle has over 300,000 visitors per year, making it one of the most visited castles in Germany.The first fortress on the mountain was constructed in the early 11th century. Over the years the House of Hohenzollern split several times, but the castle remained in the Swabian branch, the dynastic seniors of the Franconian-Brandenburgian cadet branch that later acquired its own imperial throne. This castle was completely destroyed in 1423 after a ten-month siege by the free imperial cities of Swabia. A larger and sturdier structure was constructed from 1454 to 1461, which served as a refuge for the Catholic Swabian Hohenzollerns, including during the Thirty Years’ War. By the end of the 18th century it was thought to have lost its strategic importance and gradually fell into disrepair, leading to the demolition of several dilapidated buildings. Today, only the medieval chapel remains.