When Cambodia opened up to tourism in the 1990s, Ly -- who speaks Khmer, Russian, French and English -- became a licensed tour guide to earn more money.

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Warren, who founded Saddleback with his wife 33 years ago, gave the invocation at President Barack Obama's 2009 inauguration and penned "The Purpose-Driven Life, " a Christian self-help guide that became a mainstream best-seller.

CNN: Rick Warren's son lost in 'wave of despair'

On May 29, 1953, Hillary and Tenzing Norgay, a Sherpa guide, became the first men to climb the 29, 035 feet to the top of Everest and safely return.

CNN: Final farewell for Edmund Hillary

An accompanying album, The Guide, also became a million seller.

BBC: Youssou N'Dour's ambassador's reception

Called, simply, Parfums: Le Guide, it appeared in 1992, became a French bestseller, and is currently out of print.

FORBES: The scent of money

Mr Porser said as with Mojang's hugely successful Minecraft, Scrolls would be released unfinished for a low price to get people playing with it and helping to guide what it became.

BBC: Minecraft makers show off Scrolls project