Regrettably, it would take a calamity of global proportions (i.e. a dictator far, far worse than Hitler, severe and sudden famine, an alien invasion, etc.). In each of these cases, however, great death or destruction would probabaly follow before such a wondrous thing as world peace can happen. We would need something like these calamities to bind us together, to unite us under a common goal. It would definitely have to be something that does not involve religion (which is the biggest driver for local politics and action around the world). Whatever happens has to supercede these things otherwise, personal feelings, beliefs, and opinions enter into it and will divide us before world peace can happen. We have to learn to set aside our differences (especially religious ones) and that is very hard for us to do because of how personal our beliefs are.
