Net worth: $68.5 billion

Age: 80

Country: Spain

Industry: Retail

Source of wealth: Self-made; Inditex

Amancio Ortega is the fourth-richest man in the world thanks to his control of the Spanish fashion behemoth Inditex, which Ortega — who started out as a delivery boy for a local clothing store at 14 — turned from a small-town dress shop into one of the largest fashion empires on the planet. However, in the past year Ortega's wealth has decreased by $800 million.

Much of Inditex's success can be attributed to fast-fashion giant Zara, the company's biggest brand. The chain is changing the landscape of retail as its chic yet affordable designs continue to appeal to demanding customers who constantly crave new styles at low prices.

Yet despite Ortega's immense wealth, he lives humbly. The billionaire still eats lunch with his employees in the company cafeteria, and though he's the richest person in the fashion industry, he sticks to a simple uniform of a white shirt and blue blazer.