This article is about the symbol. You may be looking for the Nazi fort of the same name.
Black Sun

The term Black Sun (German Schwarze Sonne), also referred to as the Sonnenrad (the German for "Sun Wheel"), is a symbol of esoteric or occult significance. Its design bases on a sun wheel incorporated in a floor of Wewelsburg Castle during the Nazi era. Today, it may also be used in occult currents of Germanic neopaganism, and in Irminenschaft or Armanenschaft-inspired esotericism - but not necessarily in a racial or neo-Nazi context.