BOB ABERNETHY, anchor: We have a powerful special report today on children who live and work on the streets. The UN estimates there are 100 million such kids, seven million of them in Brazil. On her recent trip to Brazil, Kim Lawton met and followed a British Christian who is spending her life trying to rescue some of those children.

KIM LAWTON: S“o Paulo is one of the largest cities in the world, and across this bustling urban sprawl, a growing global problem: children -- millions of them -- working and living on the streets. They lead a precarious, all too dangerous life.

CALLY MAGALHAES (Co-founder, AssociaÁ“o ¡guia "Project Eagle"): Living on the streets, sleeping on the streets, they're exposed to pedophiles, to corrupt police that want to harm them in some way, to anybody who wants to do them harm, and so many of our children are murdered. Many of them die.

LAWTON: Cally Magalhaes and her husband George have made it their lives' work to try and save them.

Ms. MAGALHAES: One by one, we're trying to get the children off the streets in S“o Paulo.

LAWTON: British-born Cally is an evangelical Christian. She first became aware of the problem of street children in 1994 after reading about it in a magazine.

Ms. MAGALHAES: And as I read this magazine article I just began to cry and cry and cry and cry, and I thought, I'm not going to stay here in England with my nice job and my nice house and my nice life. I'll go and see if I can do something about it.

LAWTON: She moved to Brazil and began working in the slum neighborhoods called favelas. There, she met a Brazilian man, George, who shared her vision. They got married and founded a nondenominational ministry called AssociaÁ“o ¡guia -- "Project Eagle" -- to try and rescue street children.

LAWTON: Cally, George, and their teams of volunteers work directly in the streets, finding the kids and trying to build their trust.

Ms. MAGALHAES: Sometimes we just go and talk. Sometimes we take a bag of activities. We do drawings, and they do colorings. It's very fascinating to see what they draw. Often they draw houses and families, because that's their dream.

GEORGE MAGALHAES (Co-founder, AssociaÁ“o ¡guia "Project Eagle"): Actually, I present myself as a friend to the boy or a girl. I say, "I want to be your friend, and if I can help in some way, you can tell me what I can do to help you."

LAWTON: As they chat with the children, they try to find out their situation.

Ms. MAGALHAES: I asked him where he lived, and he wouldn't tell me. And I said, "It's okay. I'm not going to take you home. I just want to help you if I can," and he told me where his mom lives.

LAWTON: But he doesn't live with her?

Ms. MAGALHAES: No, he lives here on the streets.

LAWTON: There are two types of street kids. The first are called children on the street. They do actually live with their parents, usually in a shack or slum. But they work all day on the streets, begging or finding odd jobs.

Ms. MAGALHAES: At the end of the day they go back and give the money to their mum or stepfather or whoever, and sometimes that money is used to buy food. But more often it's used to buy alcohol or drugs or something like that.

LAWTON: Then there are children of the street, those who live here day and night. Often, they've ran away, either to escape abuse or to use drugs. Many steal to survive and to support their addictions. Some move on to more serious crimes. Children start doing drugs young here. They get high by inhaling glue and paint stripper.

Ms. MAGALHAES: They put it in what looks like a bottle of mineral water, and then they breathe that through their mouth. It's actually worse for them than if they're sniffing glue. They're so high on paint stripper.

LAWTON: Over time, Project Eagle volunteers get to know the children and then try to figure out what the best situation for them would be. Can they return home, or do they need to go into drug rehab? Gisele, who's now 16, left home years ago to live on the streets.

GISELE (translated by Ms. Magalhaes): I lived here mostly because I wanted to, but mostly because of the drugs.

LAWTON: Four months ago, she had a baby and moved back home with her mother. Today, Gisele left her baby at home, and Cally finds her hanging out on the streets again. Project Eagle also offers practical help such as food and medical assistance.

Mr. MAGALHAES: The whole Gospel is the one that not just says God bless you, but to provide everything to be necessary for the person.

LAWTON: On this day, they're bringing packages of food to kids who live in what's called a squat -- a rambling den of makeshift shanties under a bridge. More than 50 people live here, including 38 small children. These kids have all been on the streets for years. Julia is eight-and-a-half months pregnant. I asked if she's worried about having a baby here.

Ms. MAGALHAES (translating for Julia): She said it should be okay. The problem is if she goes into labor here, and she's not well; the ambulance won't come here. She has to go by foot to the hospital.