The Externsteine are a striking sandstone rock formation in the Teutoburg Forest and as such are an outstanding natural sight in Germany, protected as a natural and cultural monument. They are considered to have special cultural and historical significance. The Externsteine were interpreted by Hermann Hamelmann in 1564 as a Germanic sanctuary that had been destroyed by Charlemagne. This interpretation experienced a first peak in the second half of the 19th century with the generally emerging interest in prehistory and early history, and then enjoyed great popularity again from the 1920s to 1945. Since then, these approaches have been taken up again and again - especially in local history research - with interpretations ranging from an observatory from pre-Christian times to a Germanic cult site. Thus, the Externsteine have already been called "Germany's Stonehenge".

History and myths: The Holy Grail is assumed to be at the stone ensemble; the formations are interpreted as the teeth of a giant. According to the Weser legend of Wackensteinfels, the devil threw the boulder on rock 4 at monks and their chapel, but did not hit them. Also in esoteric literature partly fantastic interpretations can be found. Excavations, however, did not provide clear evidence of a cultic use in prehistoric or early historic times, but prove human activities only for the early High Middle Ages.