Musk the mind behind PayPal, Tesla

The idea of an 800 mph transportation system is just the latest idea from the mind of Elon Musk.

Musk is a 42-year-old engineer who co-founded PayPal and created Space Exploration Technologies (SpaceX), a private space exploration company, and Tesla Motors, an American electric car company that produces the acclaimed Tesla S model.

Musk is also chairman of SolarCity, a company he cofounded "to help combat global warming and minimize air pollution," according to his website.