I mean, they're in Mesopotamia, the land between two rivers. Like I could throw stuff down there and grow stuff. But the flooding created a problem. It would leave the silt behind, but then the sun would come and everything would dry up. So the Sumerians are presented with this challenge of how to deal with all of this dry land but having the flooding. So they're able to figure out that they're able to irrigate. They're able to take the water from the river and move it to where the crops are growing.