A site in southern Mesopotamia occupied from 'Ubaid times (6th-5th millennia BC), which grew in importance during the Early Dynastic period (3rd millennium BC) to become an important Sumerian city. Ubaid and Uruk levels are separated by a flood level. In the last century of the 3rd millennium, it was the ceremonial center of the Ur III empire which controlled much of Mesopotamia. Located south of the Euphrates and west of Basra, it has a Royal Cemetery c 2800. The arch and dome were used in constructing the tombs and they contained precious metal and stones, animal figures; shell, lapis lazuli, and carnelian mosaic inlays; gold and lapis jewelry; and evidence for the sacrifice of human attendants to accompany the dead royal master or mistress. There is also spectacular 3rd millennium BC religious architecture (the ziggurat of Nanna/Sin, the moon god), residential architecture and street plans, and texts from then to the late 1st millennium BC. It was destroyed by Elam and the Amorites, but recovered by the early 2nd millennium BC. The city later declined and was finally abandoned in the 4th century BC.