A slum, as defined by the United Nations agency UN-HABITAT,'s a run-down area of a city characterized by substandard housing and squalor and lacking in tenure security. According to the United Nations, one billion people worldwide live in slums and will likely grow to 2 billion by 2030. The term has traditionally referred to housing areas that were once respectable but which deteriorated as the original dwellers moved on to newer and better parts of the city, but has come to include the vast in… (More on Slums)