Mesopotamia is thought to be one of the places where early civilization developed. It is a historic region of West Asia within the Tigris and Euphrates river system.
Sumer lacked natural barriers to keep out enemeis. So they moved to zagros foothills.
because of the rivers, this area had arich supply of fish and waterfowl that could be used for food. The land in this area was flat and fertile, rich in nutrients. This is caused by the flooding of the rivers. Almost yearly, rain and melting snow in the mountains caused the rivers to swell.