A natural gas leak provides a flickering flame beneath a waterfall.

Peek through the gates at this oasis from the city, full of Old English charm.

An unassuming secret door once led to a legendary watering hole.

Tucked away amidst some of the most famous addresses in the world is New York's only fraction of a street.

A very classy 1920s-era bar right in Grand Central Station.

Ride the subways of yesteryear.

The oldest operating apothecary in the US has treated everyone from Thomas Edison to Mark Twain.

The "Seinfeld" diner.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

A celebration of capitalism in Midtown.

The name of this famed hospital was once a byword for the horrors of medical and psychiatric care.

The world's oldest hologram gallery and the labyrinthine laser laboratory of a holography pioneer.

This unmarked and unloved Manhattan subway grate created one of the most iconic images in American cinema.

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

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

An abandoned castle owned and ignored by Masons carries a cursed history.

The oldest surviving bridge in New York City, which reopened to pedestrians in 2015.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

Hidden in an ordinary Midtown building is a one-room museum dedicated to the greatest escape artist.

More gold than anywhere else, ever.

A hands-on traveling collection of the innovative devices of yesteryear.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

One of only two commuter aerial tramways in the United States.

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