The first ancient civilization is widely recognized as the Sumerian civilization in southern Mesopotamia (modern-day Iraq). It emerged around 3500 to 4100 BCE along the Tigris and Euphrates rivers, marking the beginning of urbanism, writing, and organized government systems. The Sumerians developed the earliest known writing system (cuneiform), built cities like Uruk and Ur, and established irrigation agriculture, thus laying the foundations of civilization.