A Crack in the Edge of the World: America and the Great California Earthquake of 1906

On April 18, 1906, a magnitude 8.5 earthquake rocked San Francisco and left the city in ruins within a minute. Today on Focus, geologist and author Simon Winchester joins the show to talk about the event's impact on human history and how recent scientific advances have revealed the ancient subterranean processes that fueled it—and almost certainly will cause history to repeat itself.