These Americans are changing the world - and they're all under 40

Each year, the World Economic Forum selects innovative and socially-minded young people to receive its Young Global Leaders award.

Awardees, who are recognized for making considerable contributions to their field and society, are all under the age of 40, and 20 of them hail from the US this year.

This year's Young Global Leaders class includes leaders from an array of backgrounds. Some are political and and community leaders, others are inventors, CEOs, philanthropists, and scientists working on revolutionary ideas.

Once chosen by the WEF, these leaders are a part of the program for five years, and they attend meetings, participate in initiatives and research, and work with the rest of the WEF's community.

Here are the 20 US leaders making a worldwide impact.