10. Ayman Hariri

•  Net Worth: $1.35 B                                                                      
•  Source of Wealth: construction, investment
•  Citizen: lebanon
•  Age: 35

Ayman Hariri is the son of slain Lebanese Prime Minister Rafik Hariri. He's involved in running Saudi Oger, one of Saudi Arabia's biggest construction companies and the source of the Hariri family fortune. Oger was part of a venture that won a $653 million contract in January 2013 to build a local branch of the Louvre museum in Abu Dhabi, due to open in 2015. His other interests include telecommunications; Oger has a major stake in Turk Telekom.