I don't think the world has ever been at peace and I don't think it ever will be.
Among the most profound statements I've ever heard from a movie was a line out of Terminator which stated that it is mans nature to destoy ourselves. No matter what we learn or how far we progress, someone will take this newfound knowledge and use it against someone else.
One of the most profound lines I have ever heard out of a movie, and one of my all time favorite lines goes like this; "Evil prevails when good men fail to act. What they should say is evil prevails."