Wewelsburg (German pronunciation: [ˈveːvəlsˌbʊɐ̯k]) 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 - three round towers connected by massive walls. After 1934, it was used by the SS under Heinrich Himmler and was to be expanded into the central SS-cult-site. After 1941, plans were developed to enlarge it to be the so-called "Center of the World". In 1950, the castle was 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.