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

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

The Neapolitan Cult of the Dead still cares for the skulls at this mini-Fontanelle.

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

Beautiful views and Roman-style statues on the Italian coast.

The glowing blue Nymphaeum of Emperor Tiberius.

Thousands of well-dressed mummies below a monastery.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

This prison on the Maltese island of Gozo is almost 500 years old, and they have the graffiti to prove it.

This subterranean necropolis holds three floors of antler-dug grave caves.

Stone Age solar temple is aligned with the sun on each equinox and solstice.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

An abandoned set from the 1980 film "Popeye," claimed and repurposed as a theme park by creative locals.

A saintly relic hidden in a Prague church basement.

An old asylum graveyard that's been abandoned for half a century attracts those seeking a dark thrill.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

Walk through Czech history in Prague's largest graveyard.

A collection of anatomical samples from one of the first anthropologists to suggest that humans reached North America by crossing the Bering Strait.

The hidden lair of an alchemist rediscovered in a 2002 flood.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

A genuine Little Shop of Horrors.

In 1943 the British military took control of this village, telling residents they had to leave temporarily. The villagers were never allowed to return.

A hundred copies of Antony Gormley's naked body stare out across the water.

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