The Internet connects billions of people and machines; it's the backbone of modern life. But tech pioneer Danny Hillis thinks the Internet just wasn't designed to grow this big -- and he fears that one big cyber-attack or glitch could shut it down and take civilization with it. To head off a digital dark age, he sounds a clarion call to develop a Plan B: a parallel system to fall back on if -- or when -- the Internet crashes.

Danny Hillis: The Internet could crash. We need a Plan B

The Internet could crash. We need a Plan B