A small island in Lake Garda that was used as a burial site, pirate hideout, and a monastery.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

The verdant mossy ruins of a Franciscan monastery lie in the remote Sintra hills awaiting exploration.

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

An alchemist's "magic door" stands in the middle of a Roman park.

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

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

Renaissance villa and gardens complete with a tormented colossus.

The world's longest known cave system.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

Summer in Scotland begins with a spectacularly wild and colorful event rooted in ancient pagan traditions.

This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

A late-medieval Dutch castle with trick fountains in its whimsical water gardens.

This macabre masterpiece of a mural is one of Francisco Goya's "Black Paintings."

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

The middle finger of modernity.

Legend says this mysterious stone head belongs to a woman who was petrified by an alchemist.

A medieval weapon rumored to have been used by the brilliant poet himself.

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

Renaissance hospital featuring a rotating door into which unwanted babies were dropped.

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

The final resting place of the poets Shelley and Keats.

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

Its appearance in "Game of Thrones" may spur on the long-awaited restoration of this medieval shipyard.