The following script is from “Children Helping Children” which aired on Nov. 25, 2012. Scott Pelley is the correspondent. Nicole Young, producer.

The things that we’re thankful for tend to come from people who devote their lives to something greater than themselves. Many folks come to that devotion late in life. But Craig Kielburger discovered it early. He was in seventh grade when the death of a boy changed his life. It was a change so profound that, through Kielburger, it has now saved and transformed lives around the globe. In that moment, 17 years ago, Craig Kielburger was struck by a profound truth — something as important as changing the world can’t be left to grown ups.

Craig Kielburger: Kids are looking to get involved. They’re searching for it. And in an era where, you know adults often are looking for meaning and purpose in their lives, kids also want to assert who they are, not just by the videogames they play or the peer groups they belong to, but by the contribution they make. And that’s part of a youth self-identity in the world. And not only is it good for the child, my God, our world needs it.

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Craig Kielburger was a child when he noticed the needs of the world. As a 12-year-old in Canada he read about the murder of a boy his age in Pakistan. Iqbal Masih was a slave in a carpet factory. Masih escaped to lead a campaign against servitude. But within two years he was silenced. Kielburger put down the newspaper and rose to speak.

Craig Kielburger: We’re talking about labor and the exploitation of children.

He made Iqbal Masih’s fight, his own. He talked to classmates, to Congress, to Parliament. To call him “precocious” is an understatement as our own Ed Bradley found out in 1996.

Ed Bradley: But what made you think you could do something about it?

Craig Kielburger: Originally, I didn’t think I could, really. But the only way we’re going to ever find out is try. So after doing some research, I just walked to my classmates and said, “Listen, I read this article. Here’s a problem. This is what I know” — which at that point was not very much — and asked, ‘Who wants to help?’

Turned out 11 friends wanted to help. With no money to start with, no wealthy parents or early backers, they met in his living room and started a charity called Free The Children.

[Ed Bradley: Why you?

Craig Kielburger: Why not? If everyone in the world could say, “Why me?” — then nothing ever would be accomplished. Why me? Because I’ve met those children. Because I’ve seen them. Because I read the story of Iqbal Masih. Why not me?]

In the 1990’s, Kielburger wanted to free children from slavery. So he went to Asia recruiting activists and government authorities to bust child sweatshops and sex traffickers. There were early successes. But, when we went overseas with Kielburger, he told us freeing children was much more complicated than he had first imagined.

Scott Pelley: What are some of the things that didn’t work out? What have you learned?

Craig Kielburger: You know, probably the lowest moment ever was the first time in Southeast Asia, when we met children who we had freed before who are back in slavery. To see that some of those same kids would end up back in the same grinding, backbreaking, desperate poverty, there is nothing that makes your heart fall more than that.

Kids he freed were being pulled back into servitude, years later, by centuries old culture and traditions shaped by poverty and illiteracy.

Scott Pelley: At the point that you saw that your original big idea wasn’t working, why didn’t you throw in the towel?

Craig Kielburger: There were points frankly where there was a frustration, anger and maybe a slight desire to throw in the towel, but never a consideration of it seriously. Because that first trip I took before I sat down with Ed Bradley and that first 60 Minutes episode that was a turning point in our lives. That first trip, I made promises to a lot of kids there that at that time there was almost nothing that Free The Children could do in practice. We didn’t have schools and projects and offices around the world. And the only thing I could promise them at that point was that I would share their stories with whoever would listen. And I just wouldn’t give up. And when you make a promise, you have to fulfill it.

The way to keep that promise, he decided, was to attack hardship and ignorance — the very roots of slavery. Today, Free The Children is in 45 countries. A $30 million a year charity building schools, providing clean water, and connecting local craftsmen to world markets where their traditions bring in good money. There are two million volunteers nearly all of them under the age of 18.

Craig Kielburger: So Free the Children today is the world’s largest network of children helping children. So what that means in practice is we inspire kids. Then we give them all the tools they need to learn about these issues: speaking tours, summer leadership camps, curriculum every week. Our bet that we’re making is if you give kids the inspiration and the tools to change the world, it’ll change their own lives also in the process. And the ripple effect is incredible.

[Volunteer: Are we ready for We Day?

Kids: We are.]

You can feel that ripple in the Free The Children celebrations that Kielburger calls “We Day.” He does as many as nine of these a year and when we came to this one in Vancouver there were 20,000 kids.

We Day’s feature acts like Nelly Furtado, Jennifer Hudson, and lectures by activists including Nobel Peace Prize winner Desmond Tutu. But listen to what happens when Kielburger takes the stage.

Craig Kielburger: We Day isn’t just a day. We Day is a movement. A movement that happens all year long.

Kielburger is joined on stage every We Day by his older brother Marc, who manages the financial side of Free The Children.

Marc Kielburger: Just like you coming together and taking action.

Scott Pelley: When we see in the stadium all those faces of all those kids, how did they get there?

Craig Kielburger: You can’t buy a ticket to We Day. Any kid can earn their way in for whatever cause they care about. Half local, half global. And they’re there. These are kids who have done, you know, bake sales and car washes and volunteered at retirement homes and local support lines and they’ve started their own charities and when they leave, they bring that inspiration. We Day is just the beginning.

We followed that bake sale money back to St. Ann’s school in Bridgeport, Conn. Free The Children recruits through schools, almost turning them into chapters of the global organization.

Scott Pelley: There is so much trouble in the world.

Magdalena Dutkowska: Yes.

When we met 11-year-old, Magdalena Dutkowska and 12-year-old Joey Hopkins, they were headed to Kenya, inspired by their first We Day.

Magdalena Dutkowska: We Day is like the biggest thing in the world, it’s like the greatest event that could ever happen and so it’s just all these important people coming to one day to one event to talk about how we can change the world.

Craig Kielburger: When a child donates their birthday money, there is an incredible responsibility that comes with that to make sure– we have kids who have walked up to us and handed us a piggy bank. There is such a responsibility to make sure that money gets to where it’s supposed to go.

Scott Pelley: When the bake sale money comes in and the piggy bank money comes in and you count that up, what’s it come to?

Craig Kielburger: Well, you know, the average kid probably gives, you know, somewhere between one, maybe five, maybe $10– over the course of a school. That’s maybe $1,500 around–

Scott Pelley: So how do you save the world on that kind of money?

Craig Kielburger: Oh, that adds up to millions and millions of dollars. Tens upon tens of millions of dollars every year for our projects. A penny is almost like a kid. People walk past pennies all the time and ignore them, think they– they’re insignificant. Kind of like kids. You don’t really think twice. Can they really make a difference? But when you bring enough young people, enough kids together, then suddenly those kids can change the world.

And this is one of the places that Kielburger set out to change, the Masaai Mara in Kenya. The Mara offers nearly every wonder of East Africa. The traditions of the Masaai people are rich but their access to water and education is among the poorest in the world.

Joey Hopkins and Magdalena Dutkowska raised enough money back in Connecticut to join other volunteers to build a new classroom here. Each year 2,400 kids lend their hands overseas.

Over the last 10 years, 130 schools have been built in Kenya. This one was finished in 2010. Now, 91 students are enrolled. Among them Sharon, Naiomi, Faith and Marcella.

Scott Pelley: Sharon, let me start with you. What does this school mean to you?

Sharon: It means a lot to me. Because, at first, I could not even talk to people like you now. I did not understand English well. But now, this school has helped me a lot to know more English and gain more confidence.

Scott Pelley: How long have you been in this school?

Sharon: One and a half years.

Scott Pelley: You’ve learned this much English in one and a half years?

Sharon: Yes.

Scott Pelley: That’s amazing.

Scott Pelley: How many of you think you’re going to go to university? Everybody.

And now a university education will be open to more students because after three weeks here, a new classroom was built by the kids of Free The Children. With two students at each desk this classroom will hold about 50.

At the end of the project, the Masaai honored Magdalena and Joey with a celebration and a traditional gift.

Joey Hopkins: I was just standing there with my goat that they gave me. I was just like, “Wow.” Our like– we did this and we gave this new education to these kids and now they are so grateful for it.

Scott Pelley: What are you going to do with the goat?

Joey Hopkins: Well, I haven’t seen my goat in awhile, actually. So I miss it, but I’m going to have to leave it here in Kenya.

Scott Pelley: Leave it here? Don’t you–

Joey Hopkins: Yeah.

Scott Pelley: –think your mother would like to have it back in Connecticut?

Joey Hopkins: I wish she would, but we can’t even have a dog let alone a goat.

Scott Pelley: What are you gonna tell the kids back at school about the experience here? What do they need to know?

Joey Hopkins: What they need to know is that poverty is a real thing. And starve– kids starving, like, that are five or four years old is a real thing. That not everyone in the world can just go downstairs, turn on the tap, and get a glass of water. And that not everyone has a proper education. And that you should really be thankful for the things you have.

By the time they cut the ribbon it was hard for us to figure which kids had gained the most. The Kenyans got a new classroom, but it was the American kids who learned, they can be the change in the world.