Ancient Mesopotamia was settled in "the Cradle of Civilization" between the Tigris and the Euphrates Rivers in what is modern-day Iraq. The Mesopotamian city-states were based on a social hierarchy in which every society member knew his place, his rights and his responsibilities. There were three distinct levels and no social mobility. Priests were at the top of the social pyramid followed by the upper class, the lower class and the slaves.
Culturall, ancient Mesopotamia made many advancements. They developed the first written language, cuneiform, a set of laws called the Code of Hammurabi, and made many artistic and architectural advancements including the development of ziggurats or step-pyramids.