Overview: This episode investigates a stage collapse at the Indiana State Fair that leaves seven concertgoers dead. Is a gas leak to blame for an explosion in New York City that levels two buildings and kills eight people in their homes? Disaster strikes on an airliner at 36,000 feet as a gaping hole suddenly rips open midflight. Engineers in Japan scramble to save the lives of millions as an epic radioactive release looms. And, how could a train crossing be the site of not one, but two disastrous auto collisions in a single year?