This scenario-based activity is meant to act as an introduction to our unit of study on the Fertile Crescent / Mesopotamia.
Rather than simply lecture about the region and why people like the Sumerians settled there, this activity allows students to think outside the box (outside our world, actually) and decide for themselves what type of environment would be best suitable for human life.
The task is simple: we want to set up a human colony on another world. This activity allows students to explore various other "planets" that have different types of environments.
One of the planets the students will study is a desert world with a curious boomerang region of land between two rivers. My hope is that most students will choose this planet, despite the deserts, as the best place to start a colony, just as the Sumerians chose the place between the Tigris and Euphrates Rivers.
I love allowing students to uncover a lesson's deeper meaning by discussing and debating interesting hypothetical situations first.