Sheldon Adelson (1933-) is an American billionaire who has made his fortune in casinos and real estate development. And he is one of the world's richest men with a personal net worth of $26 billion.

Adelson was born in a modest family in Boston, where his father was a taxi driver. From a young age, Adelson was required to work to put food on the family table. He began as a newspaper boy, and then went on to sell various goods. He also worked as broker and an investment advisor. He did attend college but soon dropped out.

He started his own business at age 16 and went on to set up dozens of companies. The major chunk of his fortune, however, came from real estate development and operating casinos.

Image: Sheldon Adelson, chief executive of the Las Vegas Sands, at the Venetian Resort in Macau. | Photograph: Mike Clarke/AFP/Getty Images