September 1 may be the official start of World War II, but it didn't start in a vacuum.
September 1 may be the official start of World War II, but it didn't start in a vacuum. Europe and Asia had been tense for years before 1939 because of the rise of Adolf Hitler and the Third Reich in Germany, the Spanish Civil War, the Japanese invasion of China, the German annexation of Austria, and the imprisonment of thousands of Jews in concentration camps. After Germany's occupation of areas of Czechoslovakia not previously agreed to in the Munich Pact and its invasion of Poland, the rest of Europe realized it couldn't try to appease Germany any longer. The United States tried to remain neutral, and the Soviet Union invaded Finland.