A crumbling hospital from the 1850s on Roosevelt Island.

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

A layered tribute to the work of mosaicist Isaiah Zagar.

Eccentric concrete mansion and museum designed and built by hand from the inside out.

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

100 massive sculptures in the Hudson River Valley.

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

Final resting place of two dozen New York City harbor ships.

The loneliest island in New York.

The oldest continuously operating farm in New York State.

Home to the infamous "Typhoid Mary" and the worst loss of life in New York's history prior to September 11, 2001.

Holding the most bodies of any cemetery in the United States.

A tunnel once abandoned now thrives with graffiti art as an off-limits makeshift gallery.

Abandoned 19th century homes once occupied by naval officers, soon to be demolished.

Ride the subways of yesteryear.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

A hip bar decorated with walls of golden skulls.

Reverend Jen's unique museum/living room showcases her troll collection.

HBO series' stage tucked away in a Greenpoint lot is the largest theatrical set of its kind in the United States.

A semi-scholarly approach to sex.

Detailed facade of a brownstone in Boerum Hill.