The document summarizes the rise of Sumerian city-states in Mesopotamia. It discusses how the Sumerians faced challenges living in their difficult environment with little rain and flooding rivers. They moved from the hills to the plains and established independent city-states, each with their own ruler and farmlands. Their solutions to problems like food shortages and controlling irrigation systems led them to develop one of the world's first civilizations with social structure, government, religion, and culture.