The Pre-Pottery Neolithic communities of this period — including the communities associated with Göbekli Tepe in Upper Mesopotamia — can in this sense be seen as a reinvention and intensification of the social tendencies that the Natufians had pioneered, now in the more favorable conditions of the early Holocene.

Klaus Schmidt and the Science of Looking More Closely

The story of the discovery of Göbekli Tepe’s significance is, in one dimension, a story about the difference between looking and seeing — and about the specific training and experience that allows a skilled archaeologist to see what others have overlooked.

When Klaus Schmidt visited the site in 1994, it had already been assessed by earlier archaeologists who had described it as probably medieval in date.

The basis for that assessment was the surface evidence: stones protruding from the mound, which the earlier observers interpreted as grave markers of the type associated with medieval Islamic burials.