Once people disappear, New York City experiences its next great crash. In this episode, we reveal the breaking point of precious metals: skyscrapers face collapse, bridges hang by a steel thread; and the fate of our nation's secret stash of gold. Meanwhile, a fatal weakness is exposed in the Gateway Arch, breweries reveal untapped potential for disaster, and horses make a surprising bid to stay alive in a life after people.

The fate of the treasures left entombed, like the mysterious Doomsday Vault, the Mona Lisa, and the Declaration of Independence. Also, Philadelphia's Liberty Bell cracks for good and San Francisco's cable cars and bridges snap.