Collapse of Mythical River Civilization Explained

Collapse of Mythical River Civilization Explained | Harappan Culture & Climate Change | LiveScience: "Ancient Egypt and Mesopotamia may be the best known of the first great urban cultures, but the largest was the Indus or Harappan civilization. This culture once extended over more than 386,000 square miles (1 million square kilometers) across the plains of the Indus River from the Arabian Sea to the Ganges, and at its peak may have accounted for 10 percent of the world population."