This 317-ton walkable art installation is an homage to Korea's "City of Steel."

Several plaster noses are hidden in plain sight around London's Soho neighborhood.

A 1,215-foot tunnel transports pedestrians beneath the River Thames.

Eighty million natural history specimens call this gargantuan museum home.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

Filled with goldfish swimming in a shallow pool of sea water, this ancient crypt is more wishing well than burial site.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

In the early Roman Empire, people deemed traitors and criminals were tossed to their deaths from this rock.

A hospital where antique dolls are given new life.

The Pope’s secret escape route.

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

A community of collapsing homes more than a mile out from the Florida coast.

Where monkeys run wild and the humans are caged.

A fashion designer's dazzling world of Japanese collectibles is hidden in a warehouse downtown.

The quiet canyon has a tumultuous history involving a doomsday cult.

After starting as a whimsical tourist attraction that eventually found its way to ruin, these renovated canals offer a lush and exotic locale on the Pacific Coast.

World-famous, Pink's still manages to keep its prized cult fetish status.

A library of rare occult books in Los Angeles.

Shop selling 500 flavors of soda has something for everyone.

America's most famous piece of self-built architecture.

Resting place of Hollywood's immortals is also site of summer film screenings.

It should come as no surprise that the best view of the Hollywood sign is from Batman's lair.

The abandoned zoo enclosures offer a perfect place to experience the other side of the bars.

Remants of foundations, streets, and streetcar tracks inhabit the cliffs where a landslide occurred in 1929.