The ancient civilization recognized for developing the first cities and complex societies is Sumer, located in present-day southern Iraq. Sumerians are credited with innovations such as the wheel, cuneiform writing, and early forms of government that laid the foundation for future civilizations. Their city-states, such as Ur and Uruk, featured monumental architecture, complex societal structures, and considerable advances in agriculture and trade. The Sumerians' contributions to writing, mathematics, and urbanization significantly influenced the development of subsequent cultures in the Mesopotamian region and beyond.