An abandoned relic of the city's failed experiment with below ground transit.

This series of Scottish caves has no clear purpose other than baffling historians.

An ultra-modern vista that has been featured in so many films the house is a celebrity in its own right.

A swing to dangle you off the very edge.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

Mysterious meeting place for UFO hunters near Area 51.

A man-made island fort that has housed soldiers, scientists, and ravers.

One man's ambition created this psychedelic log home.

This abandoned amusement park was built on a site with a dark history.

Abandoned Japanese ghost town gives a glimpse into what our own metropolises may leave behind.

The haunting, dilapidated remains of a former poorhouse on Staten Island's Greenbelt.

This Elizabethan hedge maze is one of only six in North America.

This conservatory allows a little bit of the tropics to thrive in the middle of a major Canadian city.

Tour the original street level of Port Angeles, buried underground in 1914.

One of the final concrete ships built before World War II is now a crumbling breakwater.

Historic psychiatric asylum and most-filmed location in the Great White North.

This notorious Canadian mental institution was home to some of the first LSD experiments and origin of the word "psychedelic."

A long abandoned hospital building on the outskirts of NYC.

A small but industrious mining operation that allows visitors to touch precious gems while they are still in the rock.

The largest catacomb system in the world.