Thank you, Sumerians. So now that we've checked off all five boxes, let's take a little bit of a closer look at the people of Sumer, the Sumerians. So now that we know what a civilization is, the next question is why? Why are they going to build a civilization? I think that the answer really rests in the challenge that the geography presented to the Sumerians. The geography in a sense is wonderful. I mean, they're in Mesopotamia, the land between two rivers.