Does history matter?

Does history matter? A question that is asked by many, claiming "Why do we need to know what has already happened when we can plan for the future?" This question has a simple answer, because to the future, we need to know history, if we don't know a mistake that happened in the future, we won't know not to make it in the present. Take for instance, Adolf Hitler and his betrayal attack on Russia. If he had known the outcome of Napoleon's attack on Russia and interpreted the outcome of his attack, he would be in an entirely different situation. So yes, history is important, it is a set of knowledge needed for any society to move forward as a group and embrace changes rather than live in the past and repeat the same problems over and over again.