Desc: Yellowstone Supervolcano: American Doomsday: Directed by Jobim Sampson. With Larry Davis, Shaun Dooley. Imagine a modern Pompeii, a time bomb bigger than 1, 000 Hiroshima bombs, or a disaster zone 10 million times the size of Ground Zero. Sounds impossible, but is it? Hidden below America's most famous National Park is a supervolcano.