One of Catholicism's four major basilicas has a series of papal portraits that are said to predict the end of the world.

Breathtaking and huge 430 year old maps of Italy.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

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

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

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

In the early Roman Empire, people deemed traitors and criminals were tossed to their deaths from this rock.

The spot where the fascist dictator made some of his most famous speeches including declaring war on Britain and France.

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

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

A forgotten "city of water" underneath the famous Trevi district.

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

Inside this McDonald's you can dine on your Big Mac and fries next to a 2,500-year-old Roman wall.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

This famous city eluded concrete detection until the early 2000's.

A little-known park with unusual, half-ruined structures and a mystical energy.

This 13th-century monastery chiseled into the side of a mountain is equipped with a bridge that can be lifted to protect against raids.

Cave on extinct volcano, once home to famous mathematician Pythagoras.

Two churches shoot bottle rockets at each others' bell towers in an unusual Easter celebration.

This sixth-century church housed an icon with eyes so beautiful legend has it they inspired the name of a Greek city.

This wrecked ghost ship has been rusting on a Greek beach since the 1980s.

The ruins of an abandoned medieval city where the last Byzantine emperor was crowned.

On top of a hill, this Catholic church overlooks the most Catholic island in Greece.