Sumer

Sumer is the earliest known civilization, located in the historical region of southern Mesopotamia, emerging during the Chalcolithic and early Bronze Ages between the 5th and 4th millennium BC. Like nearby Elam, it is one of the cradles of civilization, along with Egypt, the Indus Valley, the Erligang culture of the Yellow River valley, Caral-Supe, and Mesoamerica. Living along the valleys of the... (Wikipedia)