A fortified medieval basilica on the Caelian Hill preserves extraordinary frescoes and one of Rome's most beautiful hidden cloisters.

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

An unusual "skull with ears" sits in the crypt of this small church tucked away at the end of a narrow alley.

Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

One man's quest to fix his toilet unearthed over 5,000 artifacts spanning more than 2,000 years of history.

A fascinating assortment of cave dwellings, medieval ruins, and sarcophagi are being devoured by the forest.

The remains of the left arm of the levitating philosopher-saint are kept in a 13th-century Neapolitan basilica.

Remnants of a 4th-century church with vivid medieval frescoes and ancient sarcophagi hide beneath this old basilica.

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

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

An eccentric artist's abode in this small Italian town has been transformed into a surreal temple of mosaic madness.

Behind medieval walls in a corner of bustling Palermo is a breathtaking former mosque once inhabited by a wolf-taming hermit.

More than 450 years ago, an Italian nun became the first woman to paint the iconic subject.

Its interior is adorned with some of the best examples of early Christian mosaics.

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

This amazingly well-preserved villa just outside Pompeii boasts rare examples of ancient Roman paintings.

Eighteen mummies have stood guard behind the altar of this tiny church since 1833.

The world's oldest surviving anatomical theater, where "the dead are pleased to help the living."

One of the world's oldest working clocks is curiously missing the Zodiac sign of Libra.

The first Russian Orthodox church in the Catholic city of Rome in almost a thousand years.

Charles Dickens was not a fan of the ghastly wall dressings in this 6th century church.

The mummified relic of St. Catherine sits forever on a golden throne.

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

St. Francesca Romana, patron saint of drivers, resides in the church she founded.