But they're also going to invent mathematical systems based on 60. Ever wonder why there's 60 seconds in a minute? Circle is 360 degrees. 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?