The challenge is to have traditional hereditary nobility (not some pseudo aristocracy based off of confederate land-owners or anything; I mean actual barons, dukes, whatever equivalent there is in non-European cultures, etc.) in as much of the world as possible until the twenty-first century. Preferably that retain some form of feudal land tenure with actual power in their lands but other forms could be control over legislature and protection from certain forms of prosecution. Otherwise the world should be fairly similar with modern human rights and technology (Its supposed to be a challenge).