In Greek, Mesopotamia means "the land between the rivers." In should come as no surprise that the rivers are the most important geographical feature of Mesopotamia. The Tigris and Euphrates Rivers, and the fertile land between them, are the birthplace of civilization. The routine flooding of the rivers left behind a fertile layer of silt that was used for agriculture. The people of Mesopotamia built irrigation systems to bring the water from the rivers to their crops. The warm climate of the area was also favorable for farming.
Another feature of Mesopotamia is that it is very flat. The fact that no geographical barriers existed left the cities open to invasion. The fertile nature of the land made it a target. As a result, city-states and kingdoms found it necessary to build strong armies for defense.