There are places in the poorest countries of the world where steel and glass high-rises grow out of ﬁelds of slums, where mansions hide in compounds with glass-studded walls to separate them from the barrios and shantytowns. Both sides of the divide live eye to eye, nose to nose, with each other. These parallel universes are visible even in the wealthier countries; you just have to look a little harder to see them. The homeless and the chauffeured limousines use the same streets. The contrasts can be mentally deafening.