A whimsical bridge adorned with decorative dragons.

This abandoned Slovenian military barracks has become a punky-political art squat.

This was the second largest mercury mine in the world and one of the oldest preserved mine complexes in Europe.

A miniature train-ride through Slovenia's largest cave system.

The "dragon babies" of southeastern Europe.

Castle and secret tunnel withstood a siege until its owner was killed by the Holy Roman Empire, while sitting on the toilet.

This massive subterranean fissure is known as the "underground Grand Canyon."

Every day is like Christmas on this street where the traditional Neapolitan nativity scene comes to life.

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

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

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

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

The once forbidden "secret cabinet" of erotic art from excavations of Pompeii and Herculaneum.

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

Before it was buried by volcanic ash, this fast-food restaurant fed the hungry hordes of ancient Rome.

The walls and streets of the ancient city are peppered with penises.

Erotic art covers the walls of the largest ancient pleasure palace.

Ancient snack bar of the Roman Empire re-opened.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

Two stone columns flank the grand Venice square, but there were supposed to be three.

Go inside to really appreciate this 500-year-old technological masterpiece.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

"The prettiest love letters in the world" ... or so said Lord Byron.