Explore Rio's favelas through a recognised volunteer project

Brazil sometimes seems to sweat pheromones through its borders. The homeland of Gisele and Ronaldo (take your pick, you know you want at least one of them), and the sensual grotesque that is Rio's carnival.

None of them, though, glowed with sweat, tension, and glamour as much as Fernando Meirelles's hit film, City of God. Based in the favelas,more than 500 squatted slums of Rio, the film lugubriously, sensually, and distinctly voyeuristically took in the guns, drugs, and gang warfare scene of the favelas in the Sixties, Seventies and Eighties. The film brought the favelas worldwide fame, and, of course, the attention of gappers looking for adventure.

The favelas are still a dangerous world for the outsider. Built to keep the poor isolated from the city centre, they are run very much according to their own rules. The best, or at least safest, way to see them is by volunteering with a gap year volunteer organisation that has a recognised project in one the community centres.

It was the danger that brought Louisa Gibbs to the favelas. "I liked that initial feeling of being scared, the challenge of it," she says. "I didn't want to go travelling, I thought that didn't demand a lot." Inspired by books by missionaries working in Rio's slums Gibbs, 19, went to teach English with gap year charity i-to-i for four months earlier this year.

Out and about for 12 hours a day, Gibbs for the most part listened to the advice not to go out in the favelas after dark. But one night she ventured out with some friends to one of the notorious funk parties in the Prazeras favela. "The men standing outside with huge guns were a bit daunting, but it was fun," she says. "I really like the music, although it was a bit strange having eight-year-olds serving you drinks at the bar."

Drawn in by the danger, it was the sense of community that she remembers most. "The people were amazing, really open," she says. "The first day I got there they came up and were hugging me." Gibbs is starting a degree in Latin American Studies at University College London this autumn. She hopes to go back to work with i-to-i in the favelas over Christmas.

Arriving in the favelas can be a daunting experience. "To get in to the favela I had to walk up a flight of 200 steps with this big mountain of shanty towns behind it," says Nicholas Menezes, who spent a month from June to July in the favelas learning Portugese and teaching English with Volunteer Adventures. "And I was scared, my heart was beating. You'd see these people looking out at you but you didn't want to make eye contact."

Menezes came to see the favela not as a slum but as a working community, with its own rules and systems of justice. The only muggings he heard of during his time there happened on the tourist beaches of Rio. "The favela works," he says. "I felt more safe in the favela than outside. A lot of people are scared to go out. It's weird, it works both ways."

Menezes, 29, is not your conventional gapper. After six years in the City he quit in January with a list of 10 things to do before he was 30. He wanted to be in Brazil to watch the World Cup. In (he hoped) the winning country. Obviously that did not work out, but, he says, he still got a lot out of teaching. "You have to break down the kids you teach," he says. "They know they're a tourist attraction, that they have this reputation for being tough, but by the end of it I gained their trust. It was really cool."

Of course, there is more to Brazil than just the favelas - and more to volunteering than teaching English. Katy Gines spent four months in 2004 in Recife volunteering at a day care centre for children with cancer and a hospital with Gap Activity Projects.

The only trouble she had was when she was mugged on a sightseeing trip to the cultural centre of the city on election day. She was pickpocketed at the carnival by packs of entrepreneurial street kids. "You'd see little kids just coming up and grabbing your pockets," she says. "But it was OK. We had nothing on us."

What made her stay was her host family. "We got on brilliantly, really well," she says. "They were really welcoming." One of their daughters came to stay with Gines' family from August to Christmas last year and she has just been invited to another's wedding.