What caused WWII

WWII was caused by a man in Germany named Adolf Hitler by killing many of the jewish people which was also known as the holocaust or in relative terms a genocide (or massive killing of a specific type of people) he killed them because he blamed them for germany losing WWI the U.S.A. stayed out of it until Pearl Harbor when the Japanese bombed our biggest naval base then we got in on the action when we stormed the beaches of Normandy, France. There was another person like Hitler. Stalin form Russia he was Hitlers ally until Hitler stabbed him in the back then Russia became our ally's the we won WWII when Hitler killed him self some say by a pill others say by a gun shot to the head but no one knows.