Favelas have existed for more than 100 years in Brazil. There are 950 favelas in Rio. But none are listed on a map. Favelas are racially mixed and economic conditions draw people to the favela. Crowded on the hills surrounding Rio, interestingly, favelas often have multi-million dollar views of the city.
Considering favelas are often all ruled by one of Rio's three organised crime syndicates - Comando Vermelho (Red Command), Terceiro Comando Puro (Pure Third Command) and Amigos dos Amigos (Friends of Friends) - it is safe to assume favelas are not the best place for wandering gringos.
As the police often want little to do with the favelas, preferring instead to pretend they simply don't exist, crime syndicates have moved in offering protection in return for a place from which to conduct their drug business dealing cocaine and marijuana. The downside for favela residents is this has also left their young people at risk as drug syndicates recruit new members.
Although it might seem strange, there have been organised tours into the favelas for some years. Local Marcelo Armstrong has been taking tourists into Rocinha and Vila Canoas favelas since 1992 to show visitor's to Rio a more realistic view of the city.
His company Favela Tour has also helped to fund a school in the Vila Canoas favela paying for 85 per cent of its running costs.
Rocinha and Vila Canoas favelas are controlled by Amigos dos Amigos and this organised crime syndicate does not seem to mind the intrusion as long as their privacy is maintained.
As we drive through the Rocinha favela the smell of rotting rubbish lying in the street is overwhelming. Favela residences are built haphazardly from whatever materials seem to be lying around and navigated by a random series of twisting stairways, passages and walkways.
As we stop Favela Tour guide Simone points to a wall covered in graffiti.
Although we can't see them, hidden inside a concrete bunker on the opposite side of the street, sit gangsters with guns. Residents have set up tables selling various handcrafts and paintings at the van stop. The tour has provided an opportunity for favela residents to start their own business right next to the drug dealers.
As we drive deeper into the favela it is apparent life goes on here just like anywhere else. There are shops, a bank and even 'Bob's', a popular Rio fast food chain. We walk through a garage past a mechanic who ignores us, to a view over the favela stretching into the distance giving an indication of its vast size.
Rocinha favela has just three public schools. Each student can only attend school for four hours each day leaving a lot of time where most children have no adult supervision as about 90 per cent of favela residents work outside the favela. Simone tells us with shoot-outs and other illegal activities, the average life expectancy for a favela child that enters the gang is just 25 years.
We drive to Vila Canoas favela. This smaller favela, which houses 2500 residents, is vastly different.
No rubbish in the streets, well dressed residents and houses maintained. Simone tells us this is partly due to the school financed by the tour where 65 students come each day for free for an additional four hours of schooling.
The benefits have spread into the rest of the community.
Another important factor is this favela is too small and too close to the heavy security of a upmarket golf club to be useful to Amigos dos Amigos.
No drugs are dealt in Vila Canoas so its children are relatively protected.
In 2007 Brazilian President Luiz Inacio (Lula) Da Silva announced Programa de Aceleracao do Crescimento, a four year investment plan which includes better infrastructure and conditions for favelas.
Although some consider the initiative merely election propaganda, Simone feels even this small start will make a difference.
Karen Phelps visited Rio's favela courtesy of Favela Tour.