Two causes of World War II were the aggressive expansionist policies of Nazi Germany under Adolf Hitler and the desire of Japan to establish a greater East Asian co-prosperity sphere. Hitler pursued a policy of territorial expansion and rearmament in violation of the Treaty of Versailles, eventually invading Poland in 1939. Japan sought to secure resources and establish dominance in East Asia, leading to the invasion of China in 1937 and the attack on Pearl Harbor in 1941. These actions ultimately led to the global conflict of World War II.
