Göbekli Tepe "Potbelly Hill" in Turkish, is an archaeological site atop a mountain ridge in the Southeastern Anatolia Region of modern-day Turkey, approximately 12km northeast of the city of Şanlıurfa. The tell has a height of 15m and is about 300m in diameter. It is approximately 760m above sea level.
The tell includes two phases of ritual use dating back to the 10th–8th millennium BCE. During the first phase, pre-pottery Neolithic A (PPNA), circles of massive T-shaped stone pillars were erected, the world's oldest known megaliths. More than 200 pillars in about 20 circles are currently known through geophysical surveys. Each pillar has a height of up to 6m and a weight of up to 20 tons. They are fitted into sockets that were hewn out of the bedrock. In the second phase, Pre-Pottery Neolithic B (PPNB), the erected pillars are smaller and stood in rectangular rooms, also with floors of polished lime. The site was abandoned after the PPNB-period. Younger structures date to classical times.
The details of the structure's function remain a mystery. It was excavated by a German archaeological team under the direction of Klaus Schmidt from 1996 until his death in 2014; Schmidt believed that the sites were early neolithic sanctuaries used as a holy site and not used as a settlement.