This curious building hides eclectic details like medieval gargoyles alongside naked angels and Art Nouveau mosaics.

Anatomical cabinet holds unexpected treasures.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

The marble facade hides a little-known medical museum with early surgical instruments and rare copies of canonical texts.

The mystic whose incorrupt corpse still attracts the faithful.

A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

Italian cave with exceptional acoustics and an unsavory history.

The skulls and bones of thousands of soldiers line the walls of this small Italian chapel.

The mummified relic of St. Antoninus.

Medieval torture techniques with a modern conscience.

A treasure trove of Renaissance-era funerary art in a Roman church built on top of Nero's grave.

This mosaic-lined medieval church was built by the world's first admiral and still holds mass in ancient Greek.

The sinister ruins of one of the worst dam failures of the 20th century lie in this astonishing alpine setting.

Walk through a fairytale in Tuscany.

The Roman Emperor's lost summer home and grotto full of enormous sculptures sit along the Italian seashore.

An ancient artistic garden parlor full of hidden water wonders.

An incredible menagerie of more than 3 million taxidermied animals at the oldest science museum in Europe.

Virgil's many-mouthed gateway to the underworld.

One of the largest caves in the world open to the public.

The remains of a town so thoroughly destroyed by French forces that the citizens simply left.

A sunken idol welcomes parishioners to Davy Jones' Locker.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

The astonishing collection of an infamous criminologist.

Where Aleister Crowley taught magick in "La Chambre Des Cauchemars," his "Chamber of Nightmares."