Sumer was one of the world's earliest civilizations, located in the southern part of modern-day Iraq. It emerged around 4500 BCE and is known for its remarkable advancements in writing, architecture, and governance. The Sumerians developed one of the first writing systems, called cuneiform, which allowed them to record their history and transactions. The Sumerians also made significant contributions to mathematics and astronomy, creating a base-60 number system that is still used today for measuring time. Their city-states, such as Ur and Lagash, were centers of trade and culture, influencing later civilizations in the region.