Who built the ziggurat in what time period?

The ziggurat, a massive terraced structure, was built by the ancient Sumerians in Mesopotamia around the 3rd millennium BCE. The most famous example, the Ziggurat of Ur, was constructed during the reign of King Ur-Nammu around 2100 BCE. These structures served as temples and were dedicated to the moon god Nanna, reflecting the religious and cultural practices of the time.