 Under the castle Teck is the 35 m long and 9 m high fabled Sibyllenloch, on the other side the 22 m long Sibyllenhöhle.It was only in 1937 discovered during construction work and was explored in 1977.During excavations in Sibyllenloch 1898/99 over 2,000 skeletal remains of cave bear, cave lion, cave hyena and wild horse were found.