Hitler's actions: Reoccupation of the Rhineland 

Description of each element: After germany signed the Treaty of versailles, which called for war payments for germany's defeat, which caused a huge loss on militar resources and lose control of the militarized Rhineland. 

Why do you believe that it was a cause of WWII?: Because hitler wanted to take his country out of that pit of shame after the huge loss of military resources at rhineland, therefore, he canceled the whole treaty and started his own plan to claim back rhineland and start an army once again.

Hitler's Actions: The Nazi-Soviet Nonaggression Pact

Description of each element: Hitler wanted to avoid going into a war against the U.S.S.R., the soviets got land, some parts of poland and the Baltic states, although this pact didn't last long two years later when hitler decided to attack the U.S.S.R.

Why do you believe that it was a cause of WWII?: Hitler wanted to recover lost land during the World War I, which they lost miserably, so he came up with the Pact, because of the two front war, germany got attacked by all sides. Therefore wanted to start this pact with the Soviets so he could slip into poland and take it back without getting into a fight against the U.S.S.R.