A perfect world! This brings to mind the historical Tower of Babel and why it was built. I think it represented all the dissension going on in the world, the separateness of nations and peoples. Atlantis also had that problem too, I read somewhere.
Now, if you want peace and harmony in the world you need to begin with the individual, for the one represents the many. Gandhi said, "Be the change you want to see in the world." What more can one add!
For the individual to achieve peace and harmony within they must begin to explore their inner being. See:
"The Purpose of Life" by Sogyal Rinpoche