The historic region of Sumer is located in present-day Iraq, particularly in the southern part known as Mesopotamia. Sumer is recognized as one of the world's earliest civilizations, emerging around 4500 BCE. It was characterized by city-states such as Ur and Uruk, known for their advancements in writing, architecture, and agriculture. Sumerians pioneered the use of cuneiform writing and established complex societal structures that profoundly influenced subsequent cultures in the region.