Dug as a secret royal escape route, the tunnel became a wartime bomb shelter and dumping ground for vintage cars.

Skulls from the plague of 1656 and World War II bombings are united by a cult dedicated to caring for the ancient dead.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

A rococo room covered entirely in porcelain originally constructed for another royal residence.

These "anatomical machines" are only one of the many strange items in this Italian crypt.

This Neapolitan exhibition hall grants weird and wonderful insight into the intricacies of human biology.

An unusual "skull with ears" sits in the crypt of this small church tucked away at the end of a narrow alley.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

For decades, vendors have sold clothes once worn by American soldiers who stormed Italy in the 1940s.

Run by a eugenics advocate, this aging institution conducted secret radiation experiments sponsored by Quaker Oats.

The decaying ruins of Wales' first asylum for the mentally ill.

A long abandoned hospital building on the outskirts of NYC.

This real life asylum of horrors is now an abandoned ruin that hides the unbreakable code to one patient's insanity.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

Unlike other abandoned asylums this empty institution welcomes visitors, just don't go in the buildings.

Once a place of peaceful repose, this sanitarium now faces an uncertain future.

This abandoned asylum in Wales might look haunted, but it's still beautiful.

The abandoned husk of a mental institution that failed to save a Jazz Age icon still sits nearly unchanged.

One man's ambition created this psychedelic log home.

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

The remains of a deserted 1800s farming community can be found in Little River State Park.

A well-preserved Ancestral Puebloan ruin tucked beneath a desert cliff.

This crumbling UFO is one of only a few remaining "moveable ski chalets" of its kind.

A key producer of charcoal iron in the early 1800s, the structure still stands today.