Via Chris Blattman via Africa Unchained, a map of the great slums of the world. They're everywhere, of course, but not always in the millions of people. According to this map, the largest are in Mexico City, Caracas, and Bogota. If you've ever seen these slums, they vary in degrees of misery. The worst I've experienced at this scale are that giant ring of extreme poverty around Mexico City and the massive poverty of Bombay. It's only going to grow.