WWII Time Line By Jbeverly23 Aug 23, 1939 Germany and the Soviet Union sign theNazi-Soviet Non-Aggression Pact Germany and the Soviet Union sign the Nazi-Soviet Non-Aggression Pact Sep 1, 1939 Germany invades Poland, starting World War II Sep 3, 1939 Britain and France declare war on Germany Jun 22, 1941 Germany invades the Soviet Union Dec 7, 1941 The Japanese launch a sneak attack on Pearl Harbor, Hawaii Aug 6, 1945 The United States drops the first atomic bomb on Hiroshima, Japan Aug 9, 1945 The United States drops a second atomic bomb on Nagasaki, Japan