From the excavations at Göbekli Tepe, 20 km northeast of Urfa.

The archaeological mound includes two phases of ritual use dating back to the 10th-8th millennium BC. During the first phase (PPNA = Pre-Pottery Neolithic A), circles of massive T-shaped stone pillars were erected. More than 200 pillars in about 20 circles are currently known through geophysical surveys. Each pillar has a height of up to 6 m (20 ft) and a weight of up to 20 tons. They are fitted into sockets that were hewn out of the bedrock. In the second phase (PPNB = Pre-pottery Neolithic B), the erected pillars are smaller and stood in rectangular rooms with floors of polished lime. A few humanoid figures were excavated, and animal figures too (crocodile, lion, wild boar).
The site was deliberately backfilled sometime after 8000 BC: the buildings were buried under debris, mostly flint gravel, stone tools, and animal bones that must have been imported from elsewhere. Younger structures at the site date to classical times. The function of the structures is not yet clear. The most common opinion, shared by excavator Klaus Schmidt, is that they are early neolithic sanctuaries (the oldest found up to now).

Correspondent: J.M.Criel, Antwerpen.
Source: (amongst others) Website of ‘ancient-wisdom.co.uk’ & Wikipedia.