Religion
The people of Ancient Mesopotamia were polytheistic. This means they worshiped many gods. They had a designated priest who would ascend into a ziggurat, to enter the temple at its zenith*. It was required of the Mesopotamians to be in constant worship, but people could not always be praying constantly. So, they left elegant crafted statues of themselves in the ziggurat, so they could be constantly in the god's presence. Also, the priest was responsible for giving the gods' food at meal time.
A ziggurat is pictured above, the temple is the box on top. The statues that the people placed in the temple are pictured below.
*Zenith - summit, peak