The Externsteine are a distinctive rock formation located in the Teutoburger Wald region of northwestern Germany, not far from the city of Detmold at Horn-Bad Meinberg. The formation consists of several tall, narrow columns of rock which rise abruptly from the surrounding wooded hills. The name probably means "stones of the Egge".
Externsteine is a natural outcropping of five sandstone pillars, the tallest of which is 37.5 meters high and form a wall of several hundred meters length, in a region that is otherwise largely devoid of rocks. The pillars have been modified and decorated by humans over the centuries. The geological formation consists of a hard, erosion-resistant sandstone, laid down during the early Cretaceous era about 120 million years ago, near the edge of a large shallow sea that covered large parts of Northern Europe at the time.
It´s not really known if and for what the rocks were used by the people over the course of history. Some even think the Externsteine are a source of spiritual power. Although I´m not a superstitious person I could feel the power of this place and could sense that the rocks must have made quite an impression on people from Stone Age to present times.
There is really something magic in that place, when you are in that area you should visit it and bring a camera (and maybe the black and white film I left home)