The Barbarossa Cave (German: Barbarossahöhle) is an anhydrite cave (gypsum cave) in the Kyffhäuser Hills near Rottleben in the east German state of Thuringia. It is a cave with large caverns, grottos and lakes. The anhydrite has formed gypsum on the surface due to the air moisture in the cave and, as a result, has increased in volume. The resulting layers of gypsum gradually separate from the underlying rock and hang like wallpaper from the walls and ceilings of the underground caverns.