World War II was more significant than World War I in several ways. It involved total warfare that impacted societies on an unprecedented scale and marked the end of European colonial empires. It diminished the power of countries like the United Kingdom and France while elevating the United States as a new global superpower through its use of atomic weapons against Japan, which also ended the war. The document provides context on the events leading up to World War II and lists key turning points and battles between 1931 to 1945.