Ancient Mesopotamia, by the Tigris and Euphrates Rivers, where agriculture and cities first developed, was divided ecologically between two zones - the southern zone of Sumer and Akkad, and the northern zone of Subir, where present-day Syria, Iraq, and Turkey meet. ArchaeoSim tells the story of ancient Subir.
Rain-fed cereal cultivation in this area was bounteous and extensive, across low-rolling plains similar to the Ukraine and Kansas. Essentially, all grain was grown for the state, and stored by the state. People were paid rations of grain based on their needs and the kind of work they did.