After the end of the last Ice Age, people settle in areas where they can exploit the local species of wheat and barley, and animals such as gazelle. Most of these settlements occur in an arc, the so-called Fertile Crescent, stretching from the southern tip of the Dead Sea north toward the Anatolian plateau, moving east to the northern Mesopotamian plains, and ending in southwestern Iran. In the eastern Mediterranean, this culture is known as Natufian and lasts more than a thousand years, from around 11,000 B.C. to about 9300 B.C., when the sites appear to be abandoned. By 8500 B.C., permanent settlements appear in large numbers where an increasingly wider range of domesticated plants and animals offer an ever more reliable form of subsistence. As these new communities grow, more elaborate forms of architecture and artistic representation reflect an increasingly differentiated social hierarchy. In the third millennium B.C., during the Early Bronze Age, local city-states develop. These are variously linked by trade with Egypt, north Syria, and Anatolia.