One of the main reasons that led subsequently to the beginning of the Second World War is the Great Depression. The economic depression that hit Europe between the two world wars was the reason for the rise of Hitler and his strengthening, who blamed the Jews, free masons, bankers, and Western European democracy for the economic crisis. Thus he gained popularity among the poor population, along with various promises that included extending the living space for Germans as a higher race, and restoring national pride to Germany. In all of those promises and moves that he has undertaken, it can be seen German imperialist tendencies over those territories he deemed to belong to Germany. Also, from Hitler's views on democracy, Jews, homosexuals, bankers, ideological differences are seen.
Answers are: economic depression, German imperialism and ideological conflict.
