How did the Mesopotamians do their town planning?

The Mesopotamian cities were divided into three parts — the sacred area, the walled city on a mound and the outer town. In the center of a town, a sacred area called the ziggurat was built. At the top of a ziggurat was a temple, dedicated to the patron god of the city. Offices and storehouses were built in the sacred area. The walled city and the outer town were residential areas. Houses of different sizes were built. Some houses had a central courtyard with rooms around it.