What was the cause of WW2?

(http://www.history.navy.mil/photos/events/wwii-pac/pearlhbr/ph-oa.htm)
I would blame Hitler for WW2. The reason why is because of his thirst for domination. He also wanted to get rid of any one that wasn't "the master race." Second, I would blame the allies for WW2. If it wasn't for the treaty that ended WW1 then the Germans wouldn't have gone into a depression, which wouldn't have made them broke. The third thing I blame the war for is the Natzies. I mean if Hitler didn't have any people to follow him then there wouldn't have been a 2nd world war. The Forth thing is I would blame the A Bomb for the war. The reason why is because of America bombed 2 Japanese cities to try to end the war. Finally the fifth thing that i would blame the war for is FDR. Because he declared war on Japan for the bombings of pearl harbor.