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

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

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

Under a glass sidewalk lie the remains of some of Manhattan's oldest buildings.

This little museum is built on a theater that was once a wildly elaborate speakeasy.

Amid the bustle and noise of the Financial District hides a secluded garden oasis above the city streets.

A treasure trove of artifacts, books, and artwork from the "golden age" of exploration.

Tucked in the back of this amazing antique store is an important piece of medical history.

Skulls and skeletons are omnipresent in this church dedicated to souls trapped in purgatory.

People have been living in the cave houses on this Italian hillside since the Neolithic era.

Ruins of a historic medical facility sits eerily by the water.

Home of Philip Johnson, one of the 20th century's most influential architects.

An Escher-inspired library dedicated to the wonders of the human mind, yet closed to the public.

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

This abandoned ironworks was once the most important military supplier in America.

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

The grave of Mary Nasson is shrouded by witchy legends.

Explore the dark underground corridors of this graffiti-covered former military fortification.

The world's only international cryptozoology museum is host to an unrivaled collection of mysterious objects.

An abandoned 19th century quarry in the middle of the woods, remade by unnamed wanderers into a massive series of rock thrones.

This New York holdover was built to provide housing for shopgirls and still does not allow men above the lobby.

A dilapidated dock tells the story of Titanic's missed arrival.

Touching mementoes from those who didn't make it back from World War I still hang in one of New York's oldest bars.

Hidden in one of New York's oldest subway stations is the final remnant of the site of the bizarre Shakespeare Riots.