in its zenith, and the so-called "Black Sun" symbol embedded in the floor of the "Obergruppenführersaal" lie on this axis. Although both rooms appear to have a ceremonial purpose, nothing is known about if, or how, the rooms were ever used. Where a primary cistern was originally located, a vault after the model of Mycenaean domed tombs was hewn into the rock, possibly to serve as some kind of commemoration of the dead. The room is unfinished. The floor was lowered 4.80 meters. The foundation of the tower was firmed with concrete, and a gas pipe leading to the centre was embedded, suggesting that an eternal flame was probably planned for the centre of this space. Twelve pedestals were placed around the perimeter, each with a wall niche above it; the purpose is unknown. On the ground floor the "Obergruppenführersaal" (literally translated: Upper-Group-Leaders-Hall, referring to the original twelve highest ranking SS-generals, called Obergruppenführer), a hall with twelve columns joined by a groined vault, twelve window- and door-niches and eight longitudinal windows was created. The room was almost finished; the rebuilding work stopped in 1943. Assumedly it was to serve as a representative hall for the SS-Obergruppenführer. In the centre of the marbled whitish/grayish floor a dark green sun wheel (Sonnenrad) is embedded. The axis of the sun wheel consisted of a circular plate of pure gold, which was to symbolize the center of the castle and thus the entire "Germanic world empire". Since the 1990s the ornament has been called the "Black Sun" occasionally. It is not known if the SS had a special name for the ornament nor if they attributed a special meaning to it. Possibly the sun wheel had a relation to the Germanic light- and sun-mysticism which was propagated by the SS. Today it is used as a symbol in Neo-Nazism and in a variety of subcultures. However, the ornament has only been linked to the esoteric neo-Nazi concept of the Black Sun after 1991. The Latin inscription above the entrance "Domus mea domus orationis vocabitur" ("My house shall be called a house of prayer") reminds of the prince-episcopalian chapel which was originally located on the ground floor of the tower. The upper floors were to be completed as a multi-storied hall with a big dome. It was to be a prestigious meeting hall for the entire corps of the SS-Gruppenführer. This room was only planned.