Mexico's Carlos Slim tops the Forbes list as the world's richest man for the fourth year in a row.
The World's Richest Billionaires

1
Carlos Slim Helu (left), age 73. Net worth: $73 billion

2
Bill Gates, age 57. Net worth: $67 billion

3
Amancio Ortega, age 76. Net worth: $57 billion

4
Warren Buffett, age 83. Net worth: $53.5 billion