Which civilization is centered around the Tigris-Euphrates river valley?

The civilization centered around the Tigris-Euphrates river valley is Sumer, which is part of ancient Mesopotamia. This region, often referred to as the "Cradle of Civilization," is significant because of its early development of urban centers, writing systems, and complex societies. The Tigris and Euphrates rivers provided fertile land for agriculture through their annual floods, enabling the growth of crops and the sustenance of large populations. As a result, Sumerians were able to establish some of the first city-states, such as Ur, Uruk, and Eridu, which became centers of culture, economy, and governance.

The importance of this river valley cannot be understated; it facilitated trade and communication while also contributing to advancements in technology, such as irrigation systems. Sumer is notable for its contributions to writing with the invention of cuneiform, as well as developments in mathematics and astronomy, laying the groundwork for future civilizations.