Piano-making empire filled with 200-year-old steam machines still churning out 1,000 instruments a year.

A posh members-only club with a literally dramatic history.

This abandoned caretaker's apartment is one of 13 left in the New York Public Library system.

This plot of old-growth forest is the largest surviving remnant of New York City's original woodland.

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

There’s a secret bunker inside the Brooklyn Bridge, but the city won’t say where.

A hyper-luxurious, 12,000- square foot home might be buried beneath Queens, still waiting to protect you from nuclear missiles.

The rough and tumble president's childhood home displays the shirt he was once shot in and the speech that saved him.

Just your average Marie Antoinette–themed speakeasy in an abandoned 19th-century subway tunnel.

“Invented in Key West, Perfected in Brooklyn."

Built as a gift to the hottest tastemaker of the time, these hidden quarters remain an Art Deco showpiece.

A WWI fighter plane and turn-of-the-century penny candy shop are among the unexpected features of this Financial District building.

Bowl in splendor, if you're lucky.

The walls are decorated with whimsical murals painted by the creator of the Madeline franchise.

An uber-secure, windowless tower of doom in the center of Manhattan is an NSA spyscraper.

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

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

The haunting, dilapidated remains of a former poorhouse on Staten Island's Greenbelt.

A restaurant on Staten Island showcases a different grandmother’s cooking every night.

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

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

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

Only gap in the 30,000-mile span of roads called the Pan-American Highway.

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