6. Harry Triguboff

•  Net Worth: $4.5 B                                                                      
•  Source of Wealth: real estate
•  Citizen: Australia
•  Age: 80

Harry Triguboff was one of the first Australian developers to see the potential of apartment living at a time when most of his countrymen aspired to a suburban block. In 50 years he has put up more than 55,000 apartments, earning him the nickname "High Rise Harry." His company, Meriton, has made the best of a sales downturn by ramping up serviced-apartment offerings in Sydney and in Australia's Gold Coast and buying inexpensive development sites.