#8 Jeff Bezos: Millennium clock and a trip to the moon

This Amazon CEO has got some amazing pet projects. He is spending $42 million to build a clock that will chime every year, decade, century, and millennium—for the next 10,000 years. And then there is Blue Origin, a space travel company that is to take astronauts to the International Space Station.

And he hired undersea experts in 2011 to find the engines that launched Apollo 11 in space, in march last year they were successful in locating them.

#7 Michael Dell: Historical photo collection

This founder and CEO of Dell Inc, with his wife Susan, run a charitable foundation dedicated to help kids in urban poverty.

Dell also puts his money into more offbeat causes. In 2010, he bought Magnum Collections,  that includes more than 180,000 of some of the nation's most important and memorable photographs taken since 1947. He houses the collection at the Ransom Center museum in Austin, Texas.

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