Indus Valley Civilization Important Facts: Earliest Civilizations of the World: Around 3500 B.C., the first cities developed in Mesopotamia– located in the river valley of the Tigris and the Euphrates. Followed by Egyptian Civilizations in the Nile River Valley beginning around 3400 B.C. The Indus Valley Civilization(flourished between 2500-1500 B.C. with its peak period ranging between 2250-1750 B.C.). The Chinese Civilization in the Huang Ho or Yellow River Valley, beginning around 1583 B.C. Geographical Extent: Manda in J&K