What was the purpose of ziggurats in Sumer?

Ziggurats in Sumer were primarily constructed as monumental structures with a religious significance, serving as temples for the worship of the gods. These stepped pyramids exemplified the Sumerians' beliefs about the cosmos and the divine. Each ziggurat was dedicated to a specific deity and was regarded as a bridge between the earth and the heavens, facilitating interactions between humans and the divine.

In addition to their religious functions, ziggurats often housed important religious artifacts and were central to the civic life of the city-state, as they served as focal points for ceremonies and gatherings. The elaborate architecture, which included terraces and temples at the summit, highlighted the importance of religion in Sumerian society, reflecting their cultural priorities and their understanding of governance, which was often seen as intertwined with religious authority.

Other options reflect different aspects of Sumerian life but do not accurately characterize the primary role of ziggurats; they were not primarily used for storing agricultural surplus, military fortifications, or as residences for the population.