What's Bill Gates doing with his money?

(CNN) -- Bill Gates and his wife Melinda are funding a charity of mammoth proportions -- the Bill and Melinda Gates Foundation.

CNN NewsPass VIDEO The Bill and Melinda Gates Foundation so far has donated $2.1 billion for children's global health. CNN's Sanjay Gupta reports (May 9) Play video

If you go to the foundation's Web site you'll see that the first tab on the navigation bar is labeled "Global Health," which underscores their commitment to the field.

In a rare interview, Gates tells CNN's Dr. Sanjay Gupta why he feels passionate about world health and outlines ways he sees to improve it.