Of course I am also excepting most of Europe (for the time being), Canada and Oceania. Why does the rest of the world want to leave their homes and move here? Please don't give me situation-specific excuses (e.g., war in Syria) or stale rationalizations like colonialism. The fact of the matter is that we are witnessing one of the greatest migrations in human history, which portends changes equivalent to the European settlement of North America. Are the Four Horsemen permanent residents of the rest of the world? How much longer can we keep them at bay? Does the bounty of our success also contain the seeds of our destruction?