Elon Musk
© Photo by Jordan Strauss/Getty Images for TeslaCo-Founder and Head of Product Design at Tesla Motors Elon Musk speaks onstage during Tesla Worldwide Debut of Model X on February 9, 2012 in Los Angeles, California.
He's trying to revolutionize the automobile, and now he wants to do the same thing to mass transit.

In an intriguing tweet posted Monday, Musk (@elonmusk) promises that on Aug. 12 he will unveil a new mass transit method which will revolutionize travel. He calls his invention the Hyperloop.
Will publish Hyperloop alpha design by Aug 12. Critical feedback for improvements would be much appreciated.

- Elon Musk (@elonmusk) July 15, 2013
Experts speculate it could be a series of pneumatic tubes that move passengers along a river of air.

Musk has long been critical of California's proposed bullet train and predicts his Hyperloop will get passengers from San Francisco to Los Angeles in 30 minutes. The bullet train would make the trip in three hours.