Göbekli Tepe, Neolithic site in SE Turkey, c. 9 mi (15 km) NE of Şanlıurfa, that dates to c.11,000 B.C. or earlier. Although previously known, it was first recognized as a Neolithic site in 1994 by German archaeologist Klaus Schmidt, who began excavating there the following year. Göbekli Tepe consists a number of circular or oval structures on a hilltop that rises 1,000 ft (300 m) above a valley; the structures do not appear to associated with human habitation but rather with a religious or ritual purpose. Those excavated to date generally have two monumental, T-shaped limestone slabs in an enclosure surrounded by more T-shaped slabs set into stone walls. The monolithic slabs, which were quarried nearby, range from 9–10 ft (2,5–3 m) high along the walls to up to 18 ft (5.5 m) for the central pillars and are decorated with carvings that depict animals (most commonly dangerous ones), symbols, and scenes. The structures were preserved because they were later intentionally backfilled and buried sometime after 8000 B.C. Such structures and the societal organization required to construct them have previously been assumed to have required a hierarchical agricultural society, but those at Göbekli Tepe were apparently built by hunter-gatherers.