Richard Branson may be known as the world's greatest entrepreneur, but his innovative thinking in the field of travel sets him apart as a true visionary.

He has embraced the mantra of "think big" more than any other entrepreneur out there -- often leading to great success, but occasionally to great failure.

Fortunately, he's not afraid of failure, instead he uses it as a catalyst for innovation.

Take, for example, the story of Branson's first plunge into the airline industry, which he recounts in his autobiography.

Branson and his future wife, Joan, were traveling to Puerto Rico when their flight was canceled, leaving them and hundreds of other passengers stranded at a small island airport.

So Branson picked up a phone and tracked down a chartered plane. He divided the cost of the plane by the number of seats, and charged the stranded passengers $39 to rebook their seats.

When an acquaintance approached him months later with the idea for a transatlantic airline company, Branson seized the opportunity.

Branson was not a natural student, but he was an entrepreneurial whiz at a young age.

Born in London in 1950, his earliest business ventures included growing Christmas trees and breeding budgerigars.

He launched Student magazine as a 16-year-old; the magazine evolved into a mail-order record company, which evolved into a chain of record shops, which evolved into a recording studio and record label that eventually became the basis for the Virgin empire.

When it came to promoting his companies, Branson was never afraid to go all-out.

He performed a series of daring feats to raise awareness of Virgin Atlantic, including an attempt to break the transatlantic speed record via powerboat (he eventually succeeded). He also became the first person (along with Per Lindstrom) to cross both the Atlantic and Pacific oceans in a hot air balloon.

As new opportunities arose in the airline industry, Branson expanded his holdings. At various times, he has bought or launched (and occasionally sold) airlines in Belgium, Australia, Nigeria, the United States, and elsewhere.

Airlines bearing the Virgin name may be the most recognizable component of Branson's travel empire, but the entrepreneur is also operates a railroad company in Britain. That venture was inspired by a trip on Japan's high-speed rail.

Of course, the biggest buzz generator in Branson's travel portfolio is Virgin Galactic, the space travel company that claims it will soon start transporting tourists into sub-orbital space for $200,000 a pop.

And through his newest venture, Virgin Galactic, the entrepreneur seeks to explore the deepest trenches of the ocean.

By "thinking bigger" than anyone else, Branson has created an unparalleled travel empire that extends from from land to sky, and from ocean to outer space.

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