A picture a day keeps the Dr away

In geological time of the lower Cretaceous period about 120 million years ago, mighty sand deposits (sediment), which are solidified to horizontal sandstone originated at the edge of the large chalk sea and later, towards the end of the Cretaceous period some 65 million years ago, tectonic processes is folded and put largely upright.

The approximately 100 m thick Osning sandstone forms the first ridge of the Teutoburg Forest and runs from the Eggegebirge Ibbenbüren in largely uniform layers. In the course of millions of years, the rocks of the area highly weathered, which - while kieselig bound - comparatively hard Osning sandstone formed but a continuously exalted layer rib which was skeletonized in some places even to free-standing rock formations. The Osning sandstone strongly shapes the landscape today and can be seen in his most impressive information at the externsteine. More natural outcrops are the Dörenther cliffs, as well as on the Teutonia cliffs in Borlinghausen.

The Externsteine were a centre of religious activity for the Teutonic peoples and their predecessors prior to the arrival of Christianity in northern Europe. Research into this area was carried out as early as 1564 by Hermann Hamelmann.

However, archaeological excavations did not produce any findings earlier than the 11th century BC, other than some Paleolithic and Mesolithic stone tools dating to before about 10,000 BC. As such the precise date when people first used the rocks for rituals has not yet been established.

The last pre-Christian inhabitants of the region were Saxons until their defeat and conversion by Emperor Charlemagne. After conquering Eresburg in 772, Charlemagne is reported to have ordered the destruction of the Saxon Irminsul; (Wilhelm Teudt in the 1920s suggested that the location of the Irminsul had been at the Externsteine). There is also evidence of an early monastery, which might have been founded as early as 815. The findings, however, are not yet conclusive, though the dating of 1093 has been proven false by art historians, who date the relief to early 9th century. An inscription seems to indicate that the Bishop of Paderborn consecrated the grotto in the north-western columns as a Christian chapel in the early 12th century.

Stairs for those who want to go on the top of the Externsteine, 2012
In 1933 Wilhelm Teudt joined the Nazi Party and proposed to turn the Externsteine into a "sacred grove" for the commemoration of the ancestors. Heinrich Himmler was open to the idea, and in 1933 initiated and then presided over the "Externstein Foundation". Interest in the location was furthered by the Nazi Ahnenerbe division within the SS, who studied the stones for their value to Germanic folklore and history.

For all that the site remains of high archaeological interest. At the top of the tallest stone is a chamber, now open. There is some kind of altarstone, which may have been once used for sacrifices, later it may have been Christianized. Directly above the altarstone a circular hole is cut into the wall, facing the direction of sunrise at the time of summersolstice. Further astroarchaeological studies of Prof.Schlosser from Bochum university have shown that this orientation has been established around the year 0±50.

Some Neo-Pagans continue to believe that the Irminsul was located at the Externsteine and identify a bent tree depicted beneath the cross in a 12th-century Christian carving with it. The site has also been of interest to various German nationalist movements over the years, and continues to be a popular destination.