What river did the sumer civilization develop by?

The Sumer civilization developed by the Tigris and Euphrates Rivers, located in present-day Iraq. These rivers provided essential water resources for irrigation, which supported agricultural practices and allowed the Sumerians to establish one of the world's earliest urban societies. The fertile land between the rivers, known as Mesopotamia, became the cradle of civilization, fostering advancements in writing, trade, and governance.