War has always been considered one of the greatest evils caused by humans. It is therefore surprising that theories and views seem to prevail which consider lasting peace to be impossible. Some, even view violence as a means of enforcing political goals, consider war as the “father of all things”, and pacifism is widely discriminated. As a counterpoint to these views, Kant’s theory of Perpetual Peace is presented in this chapter. It is conceivably simple and strong: primarily (military, economic, and political) elites are interested in war, the people only have to bear the costs of wars. Therefore, between democracies in which the people governs there will no longer wage wars. I also a League of Nations to settle interstate conflicts would be established, a lasting peace in the world would be possible. The chapter presents arguments that prove that Kant’s theory is not an unrealistic idealism, but that some of the innovations he demanded have already been introduced. The founding of the United Nations was a decisive step in this regard. But also the peace movements, forms of nonviolent resistance, international economic interdependence, and the nuclear threat are forces that lend reality to the idea of world peace.