Cause of world war 2?

September 1 1939 Hitler invaded Polar from the west. Hitlers invasion drove Great Britain and France to declare war on Germany, and World War II had begun. Over the next 6 years the conflict would take more lives and property around the globe then any previous war.

On September 1, 1939, Hitler invaded Poland from the west; two days later, France and Britain declared war on Germany, beginning World War II. On September 17, Soviet troops invaded Poland from the east.