Many people call Bill Gates their hero, but he says that his job is simple.
"In many ways, being a philanthropist is easy," he writes on his blog. "Although our foundation funds a lot of efforts to help improve the world, I sacrifice little compared to the people doing the hard work that makes progress possible."
Gates says that there are millions of others who are genuinely heroic.
"These and millions of other people like them are making a difference in our world. And while they may be too humble call themselves heroes, I can think of no better word to describe them," he writes. "Their lives inspire me. I hope they'll inspire you too."
Here are five of the regular people that Bill Gates says are saving the world.