The Internet connects billions of people, businesses, 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. Want to know plan B? Watch the TED Talk.