This subterranean oyster house has been the pearl of Grand Central Station since 1913.

Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

In upstate New York, gorgeous waterfalls and a watermill are slowly being reclaimed by nature.

Avoid gangster interaction while window-shopping.

This hidden library of physiological ephemera contains centuries worth of knowledge on the vim and viscera of the human body.

A ruined mansion hidden in the woods of the Hudson Valley, home of a tragically doomed romance.

Deep under Manhattan is the largest construction project in city history. So far, the project has taken the lives of 23 workers, or "a man a mile."

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

This interactive gallery makes you feel like you've stepped into a fantasy world filled with whimsical monsters.

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

This innocent-looking townhome is actually a subway exit.

Once America's longest-manned military fort, now an abandoned hulk.

An oasis of calm amid the chaos of the boardwalk, the museum traces the heritage of this beloved beachside amusement park.

Bowl in splendor, if you're lucky.

From scholastic to sepulchral - now under reconstruction.

This abandoned subway station can still be seen on regular commuter trips.

Slyly buy a shake in the Parker Meridien lobby.

This enormous Hindu temple in Queens serves incredible dosas in its basement canteen.

This Wall Street bar was once a hub of revolutionary activity where Washington famously bid farewell to his troops.

This semi-hidden Manhattan restaurant is based out of a loading dock.

A dark, dank room in subterranean Manhattan was the site of a ghastly murder.

The loneliest island in New York.

One of the most enjoyable bits of history at Coney Island and “the most romantic ride in the world.”

The beautiful tunnel that ran from the lobby to Penn Station is still hidden underneath 34th Street.