Why were the major mesopotamian cities located along the two main rivers?

The major Mesopotamian cities were located along the Tigris and Euphrates rivers due to the fertile land provided by the annual flooding of these rivers, which deposited nutrient-rich silt ideal for agriculture. This access to water enabled irrigation, supporting the growth of crops and sustaining larger populations. Additionally, the rivers served as vital transportation routes for trade and communication, further enhancing the development and prosperity of these urban centers.