3. Alice Walton

•  Net Worth: $26.3 B                                                                      
•  Source of Wealth: Wal-mart
•  Citizen: United states
•  Age: 64

Wal-Mart heiress Alice Walton's Crystal Bridges Museum of American Art -- which she founded in 2011 -- has eclipsed 1 million visitors in under two years of operation. Not bad for the small-town Bentonville, Ark., museum, which includes works spanning five centuries from icons like Andy Warhol, Norman Rockwell and Georgia O'Keeffe. Some pieces she donated from her personal collection (which is valued in the hundreds of millions of dollars). As the biggest philanthropist of the Walton family, Alice gave more than $2 million in 2012 to support charter school initiatives.