(CNN) -- Millions of young people want to change the world. These three actually did it, and at "CNN Heroes: An All-Star Tribute," they were honored for their efforts.
Rachel Beckwith For her 9th birthday, Rachel Beckwith asked that people donate to charity: water instead of buying her gifts. She wanted to raise $300 to help provide clean water for people in need.
A little more than a month after her birthday, Rachel died after she was critically injured in a car accident. But after her death, her story of selflessness inspired thousands of people to give money to her cause. In all, Rachel's campaign raised more than $1.25 million.
Mikey Carraway Mikey Carraway was diagnosed with liver failure when he was 11. His life was saved, however, when he received a liver transplant from 18-year-old Johnny Hernandez. Hernandez was killed in a motorcycle accident.
To honor Hernandez's memory -- and to raise awareness about organ donation -- Mikey feeds the homeless through his organization, Mikey's Meals.
Justin Churchman Justin Churchman is helping change lives in Juarez, Mexico, one house at a time.
Through Casas por Cristo, he was able to accomplish a remarkable goal: building 18 homes for people by his 18th birthday.