Built by an accountant with a dream of running a grand resort, this estate has sat vacant for over half a century.

Once the extravagant escape of the Ford family, this enigmatic ruin now stands as a haunting reminder of its former glory.

One of the few Cold War-era bases with many of its original structures still standing.

The last remnants of a lakeside airport that was bulldozed overnight by the mayor of Chicago.

Surreal riveted sea forts once protected the Kent shores from German attack.

An Italian hillside ghost town.

The remains of a failed attempt at medieval nerdery are hidden deep in the woods of Virginia.

The abandoned "Ghost Mansion" was left to decay in the mountains of Northern Italy.

A meditative space out of a fantasy story.

A bizarre house filled with an astounding array of collections.

This stunning sea creature-shaped home blends into the landscape like a fantasy villa.

High atop the Eiffel Tower is a small apartment built exclusively to entertain the science elite and make the rest of Paris jealous.

A scandalous Art Nouveau collaboration that set Paris all atwitter at the turn of the century.

A haunting collection of the vanished and disappearing natural world.

A counter-culture bookstore like no other hides in plain sight in the streets of Paris.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

A museum of carnival attractions where you are invited to ride the rides.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A horde of stray cats rule in this secluded Parisian cemetery under a bridge.

This iconic Parisian bookstore doubles as the "Tumbleweed Hotel" for traveling writers.

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

France's most famous cemetery, with some of its most curious tombs.

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

Notorious artist squat renovated into legal studios.