15 young prodigies who are already changing the world

Getty Images/Dean Mouhtaropoulos

Yusra Mardini, 18, is a star swimmer who saved refugee lives.

Some kids aren't just smart, they're superstars.  

These 15 prodigies - all 18 years old or younger - are spending their childhood and teen years making the world a better place. Some use art, some use science, and some use technology. But all of them have big hearts and even bigger ideas. 

Here are their inspiring stories: