Germany's defeat in WWI had a profound impact on Hitler's ambitions and fueled his dramatic rise to power after the Great Depression. Hitler went on to boldly defy the Treaty of Versailles in 1936 by crossing into French territory and occupying Czechoslovakia in 1938. Meanwhile, the French and the British did little to intervene and an emboldened Hitler continued his policy of aggression and went on to invade Poland in 1939.