"The Externsteine [ˈɛkstɐnʃtaɪnə] are a distinctive rock formation located in Ostwestfalen-Lippe of northwestern Germany, not far from the city of Detmold at Horn-Bad Meinberg. The formation is a tor consisting of several tall, narrow columns of rock which rise abruptly from the surrounding wooded hills. The name probably means "stones of the Egge", Egge meaning ridge." [wikipedia]
Without doubt the Externsteine were an ancient ceremonial gathering place. Some mystics nowadays affirm this location having been (still being?) a central european initiation-place.
Several geomancers are committed to the idea that the Externsteine are the earthly equivalent to the "heart-chakra" of the human body.
However, in the course of the Christianisation the pagan activities were banned from this place - at least the hieratics tried to do so. In the 9th century a relief was engraved into the stone showing the Decent from the Cross. In this scene the old Germanic Irminsul, a symbol of the world-tree Yggdrasil, is shown crooked as a seat for the body of Christ.
In 1933 Heinrich Himmler, leader of the SS, who was very interested in esotericism, declared the Externsteine the new German sanctuary, central spot of the so called „Third Reich“. In general the Nazi's interest for geomancy brought this special field of (esoteric) research into bad repute in Germany, while it is much more established for example in Britain.
Today the place is a touristic attraction with thousands of visitors a year. For a little admission the visitors are allowed to climb up the stairs, that were set in the stone, to shove around the astronomical observatory, that had been set up thousands of years ago, and which is aligned along the axis of sunset on midsummer day (and even the moonrise on winter solstice may be exactly observed from this place).
There were attempts of neonazi-groups to abuse the location for their insane purposes, but this was swiftly prevented by police.
On the occaison of the celtic feasts of the year, such as Beltaine, the equinoxes, the solstices, Samhain etc., a varied selection of neo-pagans (according to celtic or nordic mythology, members of the gothic-movement, hippies, friendly weirdos, new age travellers etc) does assemble at the Externsteine, lighting fires, playing drums and didgeridoos, singing and dancing. When I visited this place the last weekend, I found several legacys of such gatherings in the so called „Bärenschlucht“, a quite impressive canyon, that is hidden from the stream of tourists nearby the stones.