Money and power I may be wrong though
The World War II strategy used by the US for attacking Japan was called the island hopping also known as Leapfrogging strategy. It was a military strategy employed by the Allies in the Pacific War against Japan and the Axis powers during World War II. They sought to bypass heavily fortified Japanese positions and devote the few Allied resources on strategically important islands that were not well defended but capable of supporting the drive to the main islands of Japan.
Every year, floods on the Tigris and Euphrates rivers brought silt, a mix of rich soil and tiny rocks, to the land. The fertile silt made the land ideal for farming.
He explored the Mississippi River and built trading posts on it
