Well if you mean WW, sorry no "only" (sorry no better term for that) WWII was caused by the germans,
WWI was "started" by Austro-Hungary, as an answer for the murder of Prince Ferdinand through serbian
nationalists, thus resulting in war declaration from Austro-Hungary against Serbia. Germany was alied
in the middle-axis and took part (after Russia entered in to help serbia),
this is where Germany entered the war, but they didn't start it.
That geezer getting shot just gave a pretext for war, just like pearl habour or 9/11.
Actually the real cause of world war 1 was the germans nearly completing the berlin to baghdad railway, which would have given them a hugely strategic advantage in the region. Fact is that this would have been unacceptable to the uk and others. If you look beyond the text books its amazing what you can discover!
As for hitler, i suppose the harshness of the treaty of versai{sp} did lead to the radicalisation of the german people, if only the same nations that implemented the treaty would learn from there mistakes.
