The skull of the patron saint of lovers lies in the Basilica di Santa Maria in Cosmedin—maybe.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

Thousands of well-dressed mummies below a monastery.

The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

Renaissance villa and gardens complete with a tormented colossus.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

Stalactites and stalagmites in a beautifully lit cave.

Pompeii's less famous neighbor is still revealing her secrets.

The underground sanctuary of a mysterious ancient cult.

The middle finger of modernity.

At the crypt of St. Mary of Eulogies and the Dead you are left alone to ponder mortality among piles of skulls.

This hidden Art Nouveau courtyard is an opulent feast for the eyes.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

A submerged archeological park still holds the wonders of a Roman Sodom.

A 16th-century horror show built in a lovely Italian garden.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

A castle in the Scottish Highlands has been continuously inhabited since the 1300s.

The oldest continual pilgrimage site in Britain was supposedly created by a gruesome beheading.

High Victorian fantasy created a fairytale castle out of a ruined fortress in Wales.

A 4,500-year-old forest is slowly being revealed from beneath the sands of a Welsh beach.

Stonehenge has nothing on Castlerigg’s views.

During this Shetland Islands celebration, hundreds of torch-carrying "guizers" lead a procession to burn a viking longboat.

The remains of a grand castle that may have inspired Bram Stoker's Dracula.