'Planet of Slums'

"In slums the world over, squatters trade safety and health for a few square meters of land and some security of tenure. They are pioneers of swamps, floodplains, volcano slopes, unstable hillsides, desert fringes, railroad sidings, rubbish mountains, and chemical dumpsâ€"unattractive and dangerous sites that have become poverty's niche in the ecology of the city."

"In this process of rampant urbanization, the planet has become marked by the runaway growth of slums, characterized by overcrowding, poor or informal housing, inadequate access to safe water and sanitation, and insecurity of tenure. UN researchers estimate that there were at least 921 million slum dwellers in 2001 and more than 1 billion in 2005, with slum populations growing by a staggering 25 million per year."