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

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

The "Seinfeld" diner.

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

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

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.

An abandoned nightclub has become a vibrant work of art.

Now abandoned, the world's first torpedo factory is crumbling into the sea.

An ethereal glowing blue ocean cave in Croatia.

These pools have been abandoned for over 20 years.

This one-time health resort was used by aristocrats around the world.

A cemetery for Slovenian notables also serves as a popular recreation space.

Florida might be at its most surreal in this museum devoted to the famed Spanish artist.

Hidden beneath the streets of London is a secret subway that only carried mail.

Ninety feet off the valley floor is an ancient dwelling put under protection of the U.S. government by Teddy Roosevelt.

Just a few miles from downtown Atlanta is a trail covered in a crazy collection of outsider art.

The fairy tale castle of the "fairy-tale king."

This massive library holds what was once the largest book collection in the world.

Elevated freight railway turned wildly successful urban park.

Try not to get slimed in Tribeca.

This abandoned subway station beneath the Waldorf-Astoria hotel is allegedly used to secretly transport presidents.

This churchyard arbor is surrounded by hundreds of gravestones placed there by author Thomas Hardy.

A theme park that suffered massive flooding during Katrina was abandoned, and now proves irresistible to trespassing explorers.