Conditions in the Fertile Crescent in antiquity were favorable for settled life, and the rise of civilization occurred along its river valleys. This band of land between the desert and the mountains was suitable for farming and was somewhat isolated by geographical barriers on all sides. The northeast is bordered by the Zagros Mountains, the north by the Taurus and Amanus ranges. On the west lies the Mediterranean Sea, and the concave southern limit is determined by the vast Syro-Arabian Desert. The Fertile Crescent is composed of Mesopotamia in the east and the Levant, or Palestine and Syria in the west. See Mesopotamia, Palestine.