The regular flooding along the Tigris and the Euphrates made the land around them especially fertile and ideal for growing crops for food. That made it a prime spot for the Neolithic Revolution, also called the Agricultural Revolution, that began to take place almost 12,000 years ago.
I believe the first civilizations developed in Mesopotamia because of the fertile land, which was good for farming, and the easy ways to get water. In other words, I think the first civilizations developed in Mesopotamia because Mesopotamia had the different resources humans would have needed to survive.
