Area of the Fertile Crescent, circa 7500 BCE, with main sites. Göbekli Tepe is one of the important sites of the Pre-Pottery Neolithic period. The area of Mesopotamia proper at this time was not yet settled by humans. Photo by GFDL (2019). CC BY-SA 3.0. Source: “Göbekli Tepe” (2020). Wikipedia. The Free Encyclopedia.