2015 World's Billionaires: From rags to richest

Hong Kong Net Worth: $33.3 blnLi Ka-Shing Asia’s wealthiest man quit school when he was 12 and worked at a watch-strap factory to support his family.

ItalyNet Worth: $20.4 blnLeonardo Del Vecchio At seven, his mother sent him to a Milan orphanage. At 14, he began an apprenticeship in an eyeglass factory. Eleven years later, he founded Luxottica.

Russia Net Worth: $9.1 bln Roman Abramovich The oil oligarch was orphaned by the age of four and raised by relatives. After dropping out of college, he served with the Soviet army before selling plastic toys from his apartment. US Net Worth: $6.6 bln Jan Koum WhatsApp’s co-founder emigrated from Ukraine at the age of 16 with his mother and swept floors in a grocery store to help pay the bills.

India Net Worth: $5.2 bln Micky JagtianiHe dropped out of accounting school, cleaned hotel rooms and drove a cab in London before running a Dubai-based retail empire.