The stunning interior of this Gothic church is covered in ornate gold details.

Ancient catacombs form the foundation for this Rococo orgy of a church.

Picturesque intersection of witchcraft and ancient Christianity.

An honorary saint of the people, Maria Adelaide became an incorrupt corpse, the clothes intact, exhaling “a strong scent of roses.”

An abandoned tuberculosis hospital said to be haunted by the patients who died within its walls.

A museum dedicated to the Spanish occult in a town that was terrorized by the Inquisition.

This Navarrese cave's history of witchcraft and pagan ritual is not just embraced, but recreated each year.

Remarkably intact Roman stone fortifications have encircled this Spanish city for centuries.

One of the largest ossuaries in Spain is packed from floor to ceiling with bones.

The oldest operating pharmacy in the world features 800-year-old recipes.

Thousands of well-dressed mummies below a monastery.

A series of abstract, silly sculptures represent the works of a great modern classical composer.

Exquisite wall sculptures carved in secret by an early quarryman in an obscure corner of the Paris Catacombs.

A 16th-century fountain marks the site of a lost medieval cemetery once filled with mass graves.

The industrial architecture honors the laborers who brought the Exposition Universelle of 1900 to life.

A sublime medieval path adorns the marble floor of one of the most beautiful Gothic cathedrals in France.

An image of the legendary saint stands in the shadow of a cathedral she liberated.

The final resting place of the "father of special effects."

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

There is a strange little carving of a person seemingly crushed by a pillar behind the remains of St. Thomas Aquinas.

The world's largest reflecting pool is just two centimeters deep.

The huge golden reliquary of a testicle-smashing saint.

A medieval church with largest and oldest collection of Renaissance frescoes in France.

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.