I'm always amused to see Hitler's dream of a continent wide Europe excused by the Treaty of Versailles.
All those saying that the Treaty of Versailles was directly responsible for WWII because we were too harsh to the Germans usually ignore the fact that Germany had been just as harsh towards France 40 years before that (1870 war) and it hadn't caused the French to become poor helpless people who couldn't help attacking the rest of Europe in reaction to the way they had been so badly treated...
When the Germans won the 1870 war they took two departments (Alsace and Lorraine) stripping France of its biggest coal fields and of 2 million people, ordered the French to pay 5 billions gold-Francs, occupied part of France for three years until it was paid.
When The Germans lost WWI they received the same treatment (except their coal fields were handed back to them). Of course there were two big differences, they were forbidden to have an army and (what I personally consider the stupidest thing done by the Treaty) their country was cut in two to give Poland an access to the sea (the Dantzig corridor). The latter was like an open wound that was never allowed to heal.
But what happened in fact was that the Germans saw that no enemy soldier had reached German land and when their government surrendered they believed that they had been betrayed by it and by the generals, that they never truly lost in fact (Modern historians have rediscovered what the German generals knew at that time. They had lost and things would only go worse for them, they threw the towel before enemy troops came to do to Germany what they themselves had done to Belgium and northern France).
That belief which held till WWII made the Germans furious about the Treaty because they had never been beaten so why should they accept to be treated as truly defeated? Then there was that corridor cutting their land in two, and to make things worse the world wide economic crisis hit Germany the hardest when the US companies withdrew all their funds. Hitler came to power because of that combination, and rode that horse to the end, but without that feeling of indignation (we never lost, we were betrayed!) there is a good possibility that things would have played out differently. So the fault resides more in the fact that noone bothered to show the Germans of that time that they had truly lost that war. And who's fault is that is a bit hard to pinpoint.
As for Germany being an innocent bystander caught by the rush to declare war in 1914 as said above, I will just remind you of the sequence:
The Austrian Archduke was murdered by a Serb. The Austrians took advantage of that to turn on the Serbs who had been making a lot of trouble in the Austrian-Hungarian empire. When the Austrians threatened the Serbs the Russians, allied to the Serbs, declared they would intervene, the Germans said they would help the Austrians, signed an alliance with the Ottoman Empire against Russia and declared war to the Russians, and the French caught by their alliance with Russia were dragged in the mess and said they would not stay neutral. Germany invaded Luxembourg, ordered Belgium to surrender and declared war to France. Great Britain declared they would protect Belgium's neutrality and when Germany invaded Belgium declared war, dragging in automatically the rest of the Commonwealth (Canada, Australia, India, New Zealand, South Africa). Then Austria declared war to Russia and Serbia, France declared war to Austria, then Great Britain declared war to Austria. And then Japan declared war to Germany.
For an innocent bystander the German Empire sure was busy...
