Arne Wilhelmsen

Arne Wilhelmsen launched Royal Caribbean Cruises in 1969. It's now one of the largest cruise ship companies in the world with a fleet of 25.The Harvard grad retired more than a decade ago, with his son Alex taking his place on the Royal Caribbean board of directors in 2003.He has also shifted almost all ownership to his three sons.Wilhelmsen made at least $500 million in 2008 when China Oilfield Services acquired drilling rig owner Awilco Offshore, in which he had 40% stake.