History of the world
Whether in prehistoric or historic times, people always needed to be near reliable sources of potable water. Settlements developed on river banks as early as 3000 BCE in Mesopotamia, on the banks of Egypt's Nile River, in the Indus River valley, and along China's rivers. As farming developed, grain agriculture became more sophisticated and prompted a division of labour to store food between growing seasons. Labour divisions led to the rise of a leisured upper class and the development of cities, which provided the foundation for civilization. The growing complexity of human societies necessitated systems of accounting and writing.
Neolithic
Around 10,000 BC the first fully developed Neolithic cultures belonging to the phase Pre-Pottery Neolithic A (PPNA) appeared in the Fertile Crescent. Around 10,700–9400 BC a settlement was established in Tell Qaramel, north of Aleppo. The settlement included two temples dating to 9650 BC. Around 9000 BC during the PPNA, one of the world's first towns, Jericho, appeared in the Levant. It was surrounded by a stone wall and contained a population of 2,000–3,000 people and a massive stone tower. Around 6400 BC the Halaf culture appeared in Lebanon, Israel and Palestine, Syria, Anatolia, and Northern Mesopotamia and subsisted on dryland agriculture.