Mr Rich: Carlos Slim

Carlos Slim (Mexico) - $74 billion, telecommunications

Slim, 71, first showed a business talent as a 10-year-old selling drinks and snacks to his family. After studying engineering, he founded a real estate company and worked as a trader on the Mexican stock exchange. Cigar-smoking Slim is known for a "Midas touch" in acquiring struggling firms and turning them into cash cows.

His enormous wealth contrasts starkly with his frugal lifestyle. He has lived in the same house for about 40 years and drives an aging Mercedes Benz, although it is armored and trailed by bodyguards.

He has become involved in combating poverty, illiteracy and poor healthcare in Latin America and promotes sports projects for the poor, but has never voiced plans to give away large chunks of his wealth to charity.

Number 2: Bill Gates

Bill Gates (USA) - $56 billion, Microsoft

Sensing the start of a personal computer revolution, Gates, 55, dropped out of Harvard University in 1975 to start Microsoft and pursue a vision of a computer on every desk and in every home. Microsoft went public in 1986 and by the next year, the soaring stock made Gates, at age 31, the youngest self-made billionaire.

In 2008 he stepped down from what is now the world's largest software firm to work at The Bill and Melinda Gates Foundation. He has given $28 billion to it.

Together with his wife Melinda and Warren Buffett, he has also convinced 57 U.S. billionaires to sign up to the Giving Pledge and publicly vow to give away at least 50 percent of their fortune during their lifetime or upon their death.

Number 3: Warren Buffett

Warren Buffett (USA) - $50 billion, Berkshire Hathaway

Buffett, 80, has run his Omaha, Nebraska-based conglomerate since 1965. Its interests run from railroads to ice cream.At only six years of age Warren purchased 6packs of Coca-Cola from his grandfather's grocery store
for 25cents and sold them for a nickel, pocketing a five cents profit.While other children of his age were playing hopscotch and jacks, Warren was up making money. Five years later Warren took his steps in the high world finance. At 11years of age he purchased three shares of Cities Services Preferred for $38 per share both for himself and his elder sister, Doris. Shortly after buying stock they fell $27 each share. A frightened but resilient Warren stood to his shares until they rose up to $40. Warren promptly sold his shares but unfortunately they again rose up to $200. This was a lesson for Warren that helped him in later years.       
In 2006 he pledged to give away 99 percent of his wealth to the Bill and Melinda Gates Foundation and family charities. So far he has given $8 billion to the Gates Foundation.

Number 4: Bernard Arnault

Bernard Arnault (France) - $41 billion, LVMH

Arnault, 62, a friend of French president Nicolas Sarkozy, was educated at the prestigious Ecole Polytechnique and joined his father's construction company at 25. He earned the reputation of a ruthless corporate raider after pushing out shareholder rivals when he started building the LVMH group in the 1990s with the Louis Vuitton, Moet and Hennessy brands.

It is now the world's biggest luxury goods group. His image as a predator stuck to him afterward when he fought in vain to acquire Gucci in 1999 and 2000. Then this week he snapped up Roman jeweler Bulgari for $5.18 billion.

Number 5: Larry Ellison

Larry Ellison (USA) - $39.5 billion, Oracle Corp

Ellison, the flamboyant Oracle founder and CEO, is known for his free, public outbursts against rivals such as German software maker SAP AG. The executive, supposedly a model for the "Iron Man" movie character Tony Stark, late last year attacked Hewlett Packard and its board for the abrupt and -- he said -- unfair sacking of longtime friend Mark Hurd. Ellison then hired him.

Ellison, who won yachting's America's Cup last year, is considered one of the "old guard" of Silicon Valley.

Number 6: Lakshmi Mittal

Lakshmi Mittal (India) - $31.1 billion, steel

London-based steel tycoon Mittal, 60, runs ArcelorMittal, the world's largest steel manufacturer.

Mittal's firm is largely funding a $29 million spiraling red tower, designed by Turner prize-winning artist Anish Kapoor and taller than New York's Statue of Liberty, that will soar over London's Olympic Park for the 2012 games.

In 2005 he spent $10 million to promote sporting talent and encourage potential Olympians in his homeland after he was disappointed by India's lone medal at the Athens Games.

Number 7: Amancio Ortega

Amancio Ortega (Spain) - $31 billion, retailAmancio Ortega, 74, started his clothing business in the 1960s making dressing gowns in his garage in La Coruna. His company Inditex owns the Zara fashion house and is now the world's biggest clothing retailer. Ortega closely guards his privacy and does not give media interviews. He announced in January that he plans to step down as chairman of the company.
Amancio was very talented even at a very young age and he never even  attended high school. He gained a job as a manager at a local clothing shop and soon realized that only rich and wealthy could afford fine clothing so he became even more determined to make a quality clothing that is accessible to all.
Ortega even being one of the richest people of world tries to keep a low profile and in fact only a few people have seen his picture. Ortega never grants interviews and rarely shows up on public events