What materials did the people of Ur use to make the ziggurat?

The people of Ur used stone to make its ziggurat. It is one of the few well preserved structures of the pre-Sumerian city of Ur. Ur was an important city-state in Mesopotamia, close to present's southern part of Iraq. It was built during the Bronze Age (21st century BC).

The materials for the Ur ziggurat were bricks of mud and a material called bitumen. If the bricks were stacked with only mud between them, they would not have lasted long.