An ancient city of Mesopotamia in the Euphrates River valley of present-day central Iraq. Its extensive ruins have yielded valuable archaeological evidence about Sumerian culture. Ancient Mesopotamian city-state located east of Babylon in what is now south-central Iraq. It lay on the Euphrates River before the course of the river changed. City ruins date to the 4th millennium BC and to Sumerian culture; archaeological evidence of the palace of Sargon and the temple of Nebuchadrezzar II has also been found