"The slum dwellers struggle to survive with little clean water and sometimes no electricity around metropolises like Rio de Janeiro, Brazil; Mumbai, India; Lima, Peru; and Istanbul, Turkey. Their shantytowns are usually vast in expanse and dense in population. In Kibera, a slum near Nairobi, Kenya, for example, more than a million people live in an area about the size of New York's Central Park." (Quoted from article)