The internal railway of one of the biggest steel plants in America has been transformed into a linear park with unique industrial views.

The secret city built by the Manhattan Project.

Wild lights and sound effects turn a walk through some caves into an eye-popping 1960s tourist attraction.

This building contains handprints that are well over a century old.

This mouldering abandoned mental hospital was once a center for progressive healing.

This abandoned cemetery is crumbling into ruin, exposing the artifacts and bodies buried there.

Collapsing castle on the Hudson river was once the storage site of military surplus business.

This abandoned ironworks was once the most important military supplier in America.

Forgotten under the construction of a new urban roadway is a small, abandoned part of town.

This forgotten graveyard in rural New York State once served a pioneering hospital.