This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

A crumbling hospital from the 1850s on Roosevelt Island.

The feral felines of Roosevelt Island have a small army of allies and an abandoned hospital all to themselves.

From scholastic to sepulchral - now under reconstruction.

A vast collection of rare books, manuscripts & extraordinary objects illustrating the history of medicine.

A once crucial portion of the Long Island railroad still lays abandoned, waiting to be turned into an urban park.

A long abandoned hospital building on the outskirts of NYC.

The first pet cemetery in the United States.

The loneliest island in New York.

This museum showcases the history and contributions of the U.S. Army to the medical industry, both on the battlefield and off.

The intriguing personal collection of a professional demon-chaser.

The site of a tragic massacre that spawned a multimedia franchise.

The inspiration for H.P. Lovecraft's horror stories and Batman's Arkham Asylum is now a condominium complex.

Beneath the mossy overgrowth covering this once-sprawling campus lies decades of history and the secrets that come with it.

A religious-themed park filled with folk art to bring biblical stories to life that fell into disrepair and now being restored.