The Sumerians were an ancient civilization that lived in Mesopotamia, the region that is now modern-day Iraq, around 4000-2000 BCE. While much is known about their culture, society, and achievements, there are still many aspects of Sumerian life that remain shrouded in mystery. For example Archaeologists have never discovered the location of their sacred city of Nibru. The Sumerians believed that their gods lived in a city called Nibru. What happened to the Sumerians and the ancient city of Ur? Today archaeologists Discover The Lost Secrets of the Sumerians.