This 16th-century monastery has been turned into a surrealist architecture compound.

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

A rather vulgar example of the transition from Latin to the Italian vernacular.

The best preserved Paleochristian basilica in Rome hides a number of oddities and secrets.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

The "Greatest Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

Ancient ruins hidden underneath a modern luxury hotel.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

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

A Nesting Doll of Churches.

Jesus' footprints and the first catacombs in the world.

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

Architectural monsters are devouring this palace's every door and window.

The final resting place of the poets Shelley and Keats.

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

A rare example of an octagonal Catholic church.

A dreamlike medieval church dug into the tuff rock, with unusual carvings and possible traces of the Templar knights.

Italian poet Dante Alighieri is entombed in this small mausoleum in Ravenna, and his hometown of Florence has never been too happy about it.

This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

Filled with goldfish swimming in a shallow pool of sea water, this ancient crypt is more wishing well than burial site.

A magnificent Neogothic tomb hides within this Italian fairytale-like forest.

The bomb-ravaged remains of of a colossal Neptune.

A gorgeous medieval library where the books are kept in chains.

Over 100 towers were built in Bologna during the Middle Ages, but only 22 survive.