One of the most important yet well-hidden museums dedicated to the history of medicine.

Architectureal fantasy quarter of Rome.

The relics of dozens of martyrs are stored in a single chapel.

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.

The remains of the left arm of the levitating philosopher-saint are kept in a 13th-century Neapolitan basilica.

An eerie, little-known Neapolitan museum filled with preserved human remains.

The burial place of an obscure North African saint was turned into a macabre body preservation factory for the 17th-century Neapolitan elite.

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

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

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

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

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

Inside this cathedral is a shoulder bone belonging to the Patron Saint of Scotland.

Berlin's oldest surviving academic architecture hosted decades of animal dissections.

Beneath the impressive baroque cathedral that rises from the center of Berlin lies the largest collection of Prussian royals in the world.

You can row a boat through this ancient underground reservoir.

A Belle Epoque bordello turned into a themed love hotel.

This Parisian gem is one of the most incredible ethnographic museums in the world.

A Parisian boutique devoted to la Sape, the elegant Congolese fashion subculture rooted in European colonization.

The historic Masonic Lodge in which the first-ever female Mason was initiated.

Collection of antique taxidermy and natural specimens, near one of Paris's oldest flea markets.

The remaining relics of the patroness of Paris lie in a chapel under a striking double spiral staircase.

The oldest and smallest cemetery in Paris is only open to the public twice a year.