Hitler's obsession with racial purity was rooted in his belief in Social Darwinism, the idea that the strongest and fittest races would survive and prosper, while the weaker races would be eliminated. He believed that the Aryan race was the most fit and that it was therefore Germany's duty to ensure its dominance.
Hitler's policies had a devastating impact on Germany and the world. The Holocaust resulted in the deaths of millions of innocent people, and World War II, which Hitler started in order to expand German territory, resulted in the deaths of millions more. Hitler's legacy is one of hatred, violence, and destruction.