25 Billionaires Who Are Using Their Money To Help The World

According to The Chronicle of Philanthropy's annual list, the 50 biggest donors in America donated $7.7 billion in 2013, a 4% increase over the previous year. The median gift was $86.1 million, and 82 causes received gifts of $1 million or more.

Mark Zuckerberg and his wife Priscilla Chan have quickly ascended to the top of The Chronicle's list. After giving away $498.8 million last year, they doubled their charitable donations to close to $1 billion in 2013.

Zuckerberg, 29, and Chan, 28, are also by far the youngest donors on the list, which skews much older than last year's. The median age of the philanthropists was 72.5.

We're looking at the top 25 donors on this year's list; check out the complete list at The Chronicle of Philanthropy.