[["WWII began on September 1, 1939, when Germany invaded Poland. Great Britain and France declared war on Germany two days later, on September 3rd.", 21.0], ["Germany was destabilized by the Versailles Treaty, signed at the end of World War I.  Hitler came to power, promising to rebuild Germany.  Hitler and Stalin signed a German-Soviet Non-aggression Pact, eliminating Hitler's risk of war on two fronts. Germany invaded Poland on September 17th, 1939.  ", 6.0], ["WWII began on August 31, 1939 when Germany invaded Poland. On December 7, 1941 Japan attacked the U.S. Pacific Fleet at Pearl Harbor, Hawaii. The U.S. declared war on Japan December 8. Germany, Japan's ally, then declared war on the U.S. December 11, bringing the U.S. fully into the war.", 4.0]]
when was world war two beginning
history