What time period were ziggurats used in?

Ziggurats were primarily used during the ancient Mesopotamian era, particularly from around 2100 BCE to 500 BCE. They served as religious temples and were constructed by civilizations such as the Sumerians, Akkadians, Babylonians, and Assyrians. The most famous ziggurat, the Great Ziggurat of Ur, dates back to the early 21st century BCE. Their use declined with the rise of other architectural styles and the fall of these ancient civilizations.