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

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

This astonishingly geometric cave has inspired everyone from Jules Verne to Pink Floyd.

Storage warehouse of the rich and famous.

The artist and New York City icon lived, worked and died in this converted carriage house owned by another iconic artist, Andy Warhol.

The name of this tiny pocket park tucked between two buildings on Manhattan's Upper West Side is Latin for its location: "seventy-one."

This curved Manhattan building was built to house the opulence of John D. Rockefeller's oil empire.

A dark patch of the ceiling at Grand Central Terminal which was not restored is still stained brown by tobacco.

Harlem park dedicated to compulsive hoarders killed by their own junk.

During the holidays, a vintage subway train whisks New Yorkers back in time.

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

NYC's legendary underground network for bovine transportation.

The "Seinfeld" diner.

Long the exclusive domain of birds and vagabonds, this little-known Central Park peninsula is open to the public once more.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

Wall Street has a new heroine, a bronze statue of a small but fierce girl.

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

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

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

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

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

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

A clock set into the concrete outside a Manhattan jeweler has been telling time underfoot for over a century.

A popular European tradition makes its way to the states on one of America's most famous bridges.