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.
Cradle of civilization
A cradle of civilization is a location where civilization is understood to have emerged. Current thinking is that there was no single "cradle", but several civilizations that developed independently, with the Fertile Crescent (Mesopotamia and Ancient Egypt) understood to be the earliest. Other civilizations arose in Asia among cultures situated along large river valleys, such as the Indo-Gangetic Plain in Ancient India and the Yellow River in Ancient China. The extent to which there was significant influence between the early civilizations of the Near East and those of East Asia is disputed. Scholars accept that the civilizations of Mesoamerica, mainly in modern Mexico, and Norte Chico, in the north-central coastal region of Peru, emerged independently from those in Eurasia.