The early civilization known for its advanced architecture, including ziggurats, is the Sumerians of ancient Mesopotamia. Ziggurats were massive terraced structures built as temple complexes, serving as focal points for religious and administrative activities in Sumerian city-states like Ur and Uruk. These impressive architectural feats were constructed from mud bricks and symbolized a connection between the earth and the heavens, where the Sumerians honored their deities. The Sumerians are also credited with pioneering writing (cuneiform), the wheel, and complex irrigation systems, greatly influencing subsequent cultures in the region and laying foundational elements of civilization in human history.