The Indus River Valley sustained a Bronze Age civilization (3300–1300 B.C.) that was located on the western Indian subcontinent. The civilization's decline may have been due to extreme climate changes and the elimination of portions of the Ghaggar Hakra river system. Situated in Mesopotamia, the Tigris Euphrates River Valley is often referred to as the "cradle of civilization." Beginning in the Bronze Age, it existed from 3100 B.C. until the fall of Babylon in 539 B.C. to the conquering Achaemenid Empire. The "cradle of Chinese civilization," the Yellow River (or Huang He or Hwang Ho) Valley can trace its inhabitants to 2100 B.C. It is believed that the first examples of the ancient Egyptian civilization was established along the Nile River Valley as early as 3150 B.C.