Standing Bear writes "One billion people live in squatter cities and, according to the UN, this number will double in the next 25 years. Stewart Brand writes in Prospect Magazine about what squatter cities can teach us about future urban living. 'The magic of squatter cities is that they are improved steadily and gradually by their residents,' writes Brand. 'Squatter cities are also unexpectedly green. They have maximum density — 1M people per square mile in some areas of Mumbai — and have minimum energy and material use. People get around by foot, bicycle, rickshaw, or the universal shared taxi.' Brand adds that in most slums recycling is literally a way of life e.g. the Dharavi slum in Mumbai has 400 recycling units and 30,000 rag-pickers. 'Of course, fast-growing cities are far from an unmitigated good. They concentrate crime, pollution, disease, and injustice as much as business, innovation, education, and entertainment,' says Brand. Still, as architect Peter Calthorpe wrote in 1985: 'The city is the most environmentally benign form of human settlement. Each city dweller consumes less land, less energy, less water, and produces less pollution than his counterpart in settlements of lower densities.'" Reader Kanel adds this note of perspective: "Kevin Kelly is another guy who wrote about slums in a very positive light, though he was more interested in self-organisation and why cities are cool, I think. Kelly also reports on the strange trend for slum tourism. What we're seeing here is that the 'slums' have become a vehicle for people to bring out their own ideas about cities, humans, and the universe at large. I have a feeling that we're not really going to learn a lot about slums if we study them through these guys."