World war II was the most destructive and widespread war in history.  World war II began on September 1, 1939 when Germany invaded Poland.  Adolf Hitler was Germany's dictator and Germany soon crumpled Poland, Denmark, Luxembourg, the Netherlands, Belgium, Norway and France. Many more countries including the United States would become involved in the war before it finally ended in 1945 when the Allied nations defeated the Axis.  On May 7, 1945 Germany surrendered and on September 2, 1945 which can be referred to as V-J Day ("Victory over Japan Day") Japan finally surrendered and the war ended.  This war involved all the great powers and most of the smaller nations of the world.