Last month, 3,000 security forces stormed one of Brazil's largest slums, taking control of an area that the country's head of security described as having been "in the hands of a parallel power" for over three decades. "We're returning dignity and territory to people," Jose Mariano Beltrame said.
Only 5 percent of the residents of Rio's favela Rocinha have access to welfare, and only 21 percent have running water indoors, Marcelo Neri, an economist with the FGV think tank, said a few days after the clean-up. According to statistics gathered between 2008 and 2009, just 12 percent of the area's population had their trash collected regularly, while only 33 percent had mail delivered.
Brazil has more than 1,000 shantytowns that together house about 6 million people, the Associated Press calculates.
The world population has grown exponentially in the past fifty years, and cities have borne the largest burden of that global population growth. In 2007, for the first time in history, people living in cities outnumbered those living in the countryside. "The present urban population is larger than the total population of the world when John F. Kennedy was inaugurated," Mike Davies writes in Planet Of Slums.
Yet in those fifty years, not just people, but also poverty have relocated to the world's urban habitats. Slums represent the worst of urban poverty and inequality, the United Nations notes in its 2003 report on shantytowns. The report shows that slums have the worst urban housing conditions, lack basic services, and are often overcrowded or located on hazardous land.
[S]lum areas have high concentrations of poverty and of social and economic deprivation, which may include broken families, unemployment and economic, physical and social exclusion. Slum dwellers have limited access to credit and formal job markets due to stigmatization, discrimination and geographic isolation. Slums are often recipients of the city’s nuisances, including industrial effluent and noxious waste, and the only land accessible to slum dwellers is often fragile, dangerous or polluted – land that no one else wants.
Below, HuffPost takes a closer look at different slums around the world. See the living conditions in some of the world's best-known slums in the gallery below: