In 1963, archaeologists from the University of Chicago and Istanbul University examined a site known by locals as Göbekli Tepe, or "Potbelly Hill." They dismissed the site at the time as merely a medieval cemetery due to the numerous slabs of stone thought to be grave markers. However, in 1993, German archaeologist Klaus Schmidt, who was doing work at another Neolithic site in nearby Nevalı Çori, heard about the report and decided to investigate it for himself. What Schmidt and his team would eventually discover would turn out to be one of the most astounding, mysterious and important archaeological discoveries in history. Laying just below the surface was the earliest known sanctuary structure ever built by humans. Somehow, a group of prehistoric hunter-gathers had managed to quarry massive slabs of stone from nearby outcroppings, some weighing as much as 7 to 10 tons with lengths of up to 18 feet. They then moved them hundreds of feet into numerous circular configurations.