Nietzsche said this was not a declaration of atheism, although he was in fact an atheist, but simply the news of an event. He called the death of God a "tremendous event," the greatest event of modern history. The news was that educated people no longer believed in God, as a result of the rise of rationalism and scientific thought, including Darwinism, over the preceding 250 years. But before you atheists run up your flags of triumph, he said, think of the implications. "The story I have to tell," wrote Nietzsche, "is the history of the next two centuries." He predicted (in Ecce Homo ) that the twentieth century would be a century of "wars such as have never happened on earth," wars catastrophic beyond all imagining. And why? Because human beings would no longer have a god to turn to, to absolve them of their guilt; but they would still be racked by guilt, since guilt is an impulse instilled in children when they are very young, before the age of reason. As a result, people would loathe not only one another but themselves. The blind and reassuring faith they formerly poured into their belief in God, said Nietzsche, they would now pour into a belief in barbaric nationalistic brotherhoods: "If the doctrines...of the lack of any cardinal distinction between man and animal, doctrines I consider true but deadly"--he says in an allusion to Darwinism in Untimely Meditations --"are hurled into the people for another generation...then nobody should be surprised when...brotherhoods with the aim of the robbery and exploitation of the non-brothers...will appear in the arena of the future."

http://en.wikipedia.org/wiki/Adolf_Hitler's_religious_beliefs