The correct answer to this open question is the following.
The cause for movement from river valley civilizations to early industrial centers was natural disasters such as floods or earthquakes as well as invasions from other city-states.
Early civilizations established next to rivers for the many advantages it represented. After many years of being nomads, humans learned agriculture techniques, settled in these places and started to grow crops during the Neolithic or Agriculture Revolution. One of the earliest or the earliest civilization registered by historians were the Sumerians. They settled in between the Rivers Tigris and Euphrates. Another important early civilization were the Egyptians that settled in next to the Nile River.
