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.
History of the world
Humanity's written history was preceded by its prehistory, beginning with the Palaeolithic Era ("Early Stone Age"), followed by the Neolithic Era ("New Stone Age"). The Neolithic saw the Agricultural Revolution begin, between 8000 and 5000 BCE, in the Near East's Fertile Crescent. During this period, humans began the systematic husbandry of plants and animals. As agriculture advanced, most humans transitioned from a nomadic to a settled lifestyle as farmers in permanent settlements. The relative security and increased productivity provided by farming allowed communities to expand into increasingly larger units, fostered by advances in transportation.