Like the cultures of the Nile or the Indus, Mesopotamia, as its name suggests ("the land between the rivers") owed its existence to a river system. Large-scale human societies had begun to grow from about 10,000BC in an arc through Syria, Palestine, Anatolia and the Zagros mountains. Starting with the first larger scale settlements at Jericho and Catal Huyuk in Anatolia, these were well built but still relatively small. It was only when sophisticated irrigation techniques were developed that the plain of southern Iraq was opened up to sustain a huge concentration of people and resources. Yet even this was still a relatively confined area: Mesopotamia had 25,000 sq km of irrigated land – similar in size to early dynastic Egypt.