Wewelsburg () is a Renaissance castle located in the village of Wewelsburg, which is a district of the town of Büren, Westphalia, in the Landkreis of Paderborn in the northeast of North Rhine-Westphalia, Germany. The castle has a triangular layout, with three round towers connected by massive walls. After 1934 it was used by the SS under Heinrich Himmler, and was to be expanded into a complex which would serve as the central SS cult-site. After 1941, plans were developed to enlarge it to be the so-called "Centre of the World". In 1950, the castle reopened as a museum and youth hostel. (The youth hostel is one of the largest in Germany.) The castle today hosts the Historical Museum of the Prince Bishopric of Paderborn and the Wewelsburg 1933–1945 Memorial Museum. History Earlier structures Predecessor buildings existed. One of these, the Wifilisburg, was defended during the 9th and 10th centuries against the Hungarians. Count built another predecessor fortification. In 1123/24, after his death, peasants whom he had oppressed demolished the building. In 1301, the Count of Waldeck sold the Wewelsburg to the Prince-Bishop of Paderborn. A document concerning this acquisition indicates that two fortresslike buildings stood on the hill, the Bürensches Haus and the Waldecksches Haus. Current structure Prince-Bishops of Paderborn From 1301 to 1589, the Prince-Bishops of Paderborn assigned the estate to various liege lords. The masonry of both predecessor buildings was integrated in the current triangular Renaissance castle. In its current form, the Wewelsburg was built from 1603 to 1609 as secondary residence for the Prince-Bishops of Paderborn, at that time . Its location is near what was then believed to be the site of the Battle of the Teutoburg Forest of 9 CE. The Wewelsburg was taken several times during the Thirty Years' War. In 1646 it was occupied and then razed by Swedish troops, by the army commanded by General Carl Gustav Wrangel. After 1650, the mostly destroyed castle was rebuilt by Prince-Bishop Theodor Adolf von der Recke and his successor Ferdinand von Fürstenberg. He carried out some architectural changes; the three towers of the castle got their baroque domes. From 1589 to 1821, the castle was the place of residence of a bursary officer (or steward). Two witch trials took place in the Wewelsburg in 1631 (a former inquisition room is placed in the basement next to the east tower). During the Seven Years' War