Remains of the First Babylon Site - Iraq
Obvious explanations suggest themselves for the riverine location of large human settlements - fertility of the well-watered valleys and plains, rich pasturage and facilities for river transport and communication. The delta land of Mesopotamia indeed owes its existence to the Euphrates and the Tigris, and here flourished the Sumerian civilization, the earliest of which there is historical knowledge. Its culture preceeded 3000BC. Not long afterwards Babylon arose higher up on the Euphrates, to dominate awhile and then to disappear.
From Wonders of the Past