Final answer:
The ziggurat, a terraced step pyramid from ancient Mesopotamian cultures, symbolized the seven realms. It was an architectural representation of the celestial hierarchy and served as a religious and economic center.
Step-by-step explanation:
Built on seven levels, the ziggurat represented the seven realms and planes of existence, the seven planets, and the seven metals associated with them, along with their corresponding colors. The ziggurat marked a significant architectural achievement for the Sumerians and later Mesopotamian cultures. These massive terraced step pyramids served various purposes; they were religious centers, economic hubs, and a symbol of the Mesopotamian pantheon's celestial hierarchy. By dedicating each level to a different entity or cosmic aspect, the ziggurat embodied the belief system of the Mesopotamians who perceived their world as interconnected with the divine realms above.