Thousand-year-old Viking runes adorn an ancient Greek lion at the entrance to the Venetian Arsenal.

The marble facade hides a little-known medical museum with early surgical instruments and rare copies of canonical texts.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

Venice's "Island of the Mad."

Hanging within this medieval church are the bones of a beast allegedly slain by a fourth-century saint.

As can be expected from a centuries old church built in a canal city, the undercroft of this house of worship is beautifully flooded.

One of Rome's most picturesque and original bridges was also a popular choice for Grand Tour artists.

Believed to be the remains of the lost Temple of Minerva, this nymphaeum has been known by its misnomer to this day.

This curious, round temple is the oldest still-standing marble building in Rome.

This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

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

A deep mark on the remains of a Roman temple, believed to be left by a legendary warrior.

The only remaining arch of the oldest stone bridge in Rome stands in the middle of the Tiber.

The ruins of the largest gladiatorial school in Rome are largely hidden under modern streets.

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

This hidden alley near the location of Rome's first theater was the site of a curious miracle.

This ancient Roman arch misled treasure hunters for centuries.

This large, circular tomb is the final resting place of the first emperor of Rome.

This ancient trail climbs the mountain where a Latin League cult worshipped Jupiter, its main deity.

The ruins of an abbey believed to have been founded by Charlemagne in the 9th century.

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

Roman-era ships unearthed...

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

The mystic whose incorrupt corpse still attracts the faithful.