Final answer:
Ziggurats were made of mud bricks, which were stacked and piled to create terraced step pyramids. Despite being made of sun-baked mud, these structures have survived for thousands of years.
Step-by-step explanation:
Ziggurats were made of mud bricks. These immense stepped towers were built by stacking and piling mud bricks on top of each other, creating a terraced step pyramid. The bricks were composed of sun-baked mud, which was the dominant building material in Mesopotamia during the construction of ziggurats. Despite being considered fragile, these mud-brick structures were able to withstand the test of time and have survived for thousands of years.