1950s noting a two stepped plateau with a ditch 100 meters from the foot of the mound. A scaled plan, based on aerial photographs, was published in 1963 which estimated the mound area at 116 hectares and the area within the circular depression as 216 hectares. Due to this large size Van Liere proposed it as the location of Washshukanni. Excavation by a joint Syrian-American expedition (by the Oriental Institute of the University of Chicago and the Syrian Directorate General of Antiquities) was conducted beginning in 1999 and ending in 2010. Initial work in 1999 included an intensive surface survey based on 10 meter by 10 meter squares. The excavation was initially led by McGuire Gibson and later by Clemens D. Reichel. The site was abandoned at the end of the 3rd millennium BC. During the 2001 excavations a 400 square meter trench opened in the residential area of the lower town found that it was prosperous and had been sacked and abandoned at that time. Thousands of clay sealings have been found on the site, indicating the existence of a complex bureaucratic system. These sealings were once used to protect doors or containers from tampering and were impressed with stamp seals. Artifacts from Hamoukar can be seen at the Oriental Institute. Eye Idols made of alabaster or bone have been found in Tell Hamoukar. Similar Eye Idols from the same period have also been found in Tell Brak, the biggest settlement from Syria's Late Chalcolithic period. Obsidian Obsidian fragments were found across a 280 hectare area with obsidian workshops located in a section of the lower town, indicating the existence of the obsidian production facilities of both weapons and tools. They were in use at least as early as several centuries before the destruction of the 3rd millennium BC city in c. 3500 BC. The volcanic rock of this type does not occur in Hamoukar area, so it must have been imported. The nearest deposits are located in the area of Mount Nemrut (today's Turkey), about 170 km north of the city. This is confirmed by chemical analysis of the obsidian. The findings were a surprise for many archaeologists, since they indicate the existence of independent trading networks in the northern Mesopotamia outside of the influence of southern cities, such as Ur and Uruk. Earliest urban warfare Excavation work undertaken in 2005 and 2006 showed that Hamoulkar was destroyed