Agriculture came to Mesopotamia around 5000 BCE. The soft soil allowed for the development of wooden plows, but agriculture would not have been possible without technology. Religion developed along with the various small cities that grew in Mesopotamia. A world of many cities, Mesopotamia was also a world of many gods, and most religions were polytheistic, following many gods, or henotheistic, believing in many gods but focusing worship on only one. Although the Mesopotamian peoples put most of their technological energy into controlling the Tigris and Euphrates, advancing mathematics, and improving their armies, they also built some of the earliest massive buildings in the world outside of Europe and Egypt, including the Ziggurat of Ur, an administrative and temple complex completed around 2100 BCE. Life in both Egypt and Mesopotamia was governed, in some ways, by the flooding of the rivers, and people in both areas had creation myths that included receding floodwaters.