The document discusses the earliest civilization that began between the Tigris and Euphrates rivers in Mesopotamia. The Sumerians were the first people to live in cities along these rivers around 3500 BC, with ordinary people working on farms, maintaining irrigation dikes, or in households, while artisans made clothes, pottery, and jewelry. The Persians traded goods with the Sumerians in one of the earliest civilizations protected by dikes along the Tigris and Euphrates rivers.