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.
Andean civilizations
The Andean civilizations were a patchwork of different cultures and peoples that mainly developed in the coastal deserts of Peru. They strectched from the Andes of Colombia southward down the Andes to northern Argentina and Chile. Archaeologists believe that Andean civilizations first developed on the narrow coastal plain of the Pacific Ocean. The Norte Chico civilization of Peru is the oldest civilization in the Americas, dating back to 3200 BCE.