Ziggurats are massive, terraced structures that were built in ancient Mesopotamia, primarily by the Sumerians, Akkadians, Babylonians, and Assyrians. These monumental buildings served as temples or religious centers dedicated to the gods, often featuring a flat top where rituals and ceremonies would take place. Their distinctive step-like design consists of a series of stacked platforms, with each level smaller than the one below it, symbolizing a connection between the earth and the heavens. Ziggurats are significant architectural achievements that reflect the religious and cultural practices of ancient Mesopotamian civilizations.