[["It began in 1939, when Germany started it by declaring war on Poland and invading. For the USA, it began on December 7, 1941 when the Japanese attacked Pearl Harbor. ", 17.0], ["The major causes of World War II were numerous. They include the impact of the Treaty of Versailles following WWI, the worldwide economic depression, failure of appeasement, the rise of militarism in Germany and Japan, and the failure of the League of Nations.", 8.0], ["How:  By Germany invading Poland in 1939 after British appeasement by Neville Chamberlian.  Some say WWII started by the Peace Treaty that ended WWI and the reparations demanded by the victors over the defeated German Empire.", 7.0]]
how when did world war two start
history