World War II Major Events Timeline By criver13 Nov 11, 1918 World War I Ends Jan 30, 1933 Hitler Appointed German Leader Sep 1, 1939 World War II Begins Sep 17, 1939 Soviet Union Invades Poland Sep 27, 1939 Warsaw Captured Dec 13, 1939 UK Wins War's First Sea Battle 1940 Miracle of Dunkirk Apr 8, 1940 Norway Invaded May 10, 1940 Churchill Becomes Prime Minister Jun 14, 1940 Paris Falls to Nazis Dec 7, 1941 U.S. Plunged Into War