Sao Paulo, Brazil - Only the steady flow of men, women and children through a rusted, grey door alert passersby that anyone lives inside the 22-story building. It's covered in graffiti: a small house - bright yellow, with a brown door, window and roof - two women's faces, and the number 911.
With an abundance of unused buildings peppering the city, low-income residents of Sao Paulo occupy vacant structures, often with the help of local social and housing rights movements. This is one of them. "We occupy [buildings] to give a social function to the properties and give houses to people without houses," said Maria Silva, one of the residents.
In other cases, several families occupy large homes, and each family rents out a single room while sharing other facilities, like bathrooms and kitchens. These structures are known as corticos (boarding houses, or tenement buildings).
Unlike the favelas, corticos consist of large, urban apartment-syle buildings shared by several families.
In Sao Paulo, rapid urbanisation was linked to a shift from agriculture to more modern industries, and as labourers moved into makeshift communities to be closer to work. While most favelas are in the peripheries of Sao Paulo, many low-income families also moved into the city centre to be closer to basic services.
Brazil experienced several decades of rapid, countrywide urbanisation. While only 35 percent of Brazilians lived in cities in the 1950s, that number has grown to 85 percent today.
"With the logic of building in the periphery for social housing, you have no infrastructure, you have no hospitals, you have no schools and you have no transportation. This generated a very big problem of social segregation. In the last two decades, there has been a very strong housing movement to talk about the right to live in the centre of the cities," said Luiz Kohara, executive secretary of the Gaspar Garcia Centre, a local group that supports the right to housing.
In 2008, Brazil lacked 5.45 million dwellings to meet its citizens' housing needs, a shortage that primarily affected the urban poor. At least seven million housing units sit vacant in the entirety of Brazil, 70 percent of which are in urban areas.
"Of the total seven million units, 6.3 million would be in condition to be occupied, and accommodate 19 million [people]. Yet, this issue has not been adequately taken into consideration in the scope of recent housing policies," UN-HABITAT found.
Brazil's former President Luiz Ignacio "Lula" Da Silva instituted the "My House, My Life" (Minha Casa Minha Vida) programme in 2009. In partnership with the private sector, Da Silva invested $18.4bn to build one million low-income housing units by the end of 2011.
The programme has continued under Lula's successor, Dilma Rousseff, and a goal was set to build another two million units from 2012-2014 with an investment of $67.2bn.
But housing rights advocates say that doesn't address the real issue. "The problem in Brazil is not a lack of housing, it's the bad distribution of housing," said Gaspar Garcia's Kohara. "This is a reflection of the social inequality in Brazil."