When Craig Kielburger first appeared on The Oprah Show in 1999, he was a 16-year-old social activist on a mission to show young people they have the power to change the world. Since that day, Oprah's Angel Network has teamed up with Craig's organization, Free The Children, and built almost 60 schools in underdeveloped countries around the world.

"We've set up groups in schools across North America. They apply and receive a curriculum about different issues facing the world—from environment to health to sustainability. Then, the students take actions from fundraisers to awareness raisers, and some of them even go overseas and volunteer," Craig says. "We're launching a challenge to a generation of kids to change the world."