Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

The Emperor Tiberius' palace of debauchery.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

Water and windows define this defensive Italian well.

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

This ritzy Italian market is built around a statue of an unforgiven heretic who was burned for his belief in an endless universe.

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

Five candy-colored villages on the Italian Riviera.

The engineering wonder and pleasure dome of a much-maligned emperor still holds undiscovered secrets.

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

The final resting place of the poets Shelley and Keats.

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

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

The yawning maw of this pagan visage is said to bite off the hands of liars.

Rome's semi-secret peephole vista is also a former Crusader stronghold.

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

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

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

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

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

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

Ever loyal to Roma, the small village of Albe in the Abruzzo region carried on until an earthquake did it in.

Architectureal fantasy quarter of Rome.

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