The graveyard is filled with beautiful funerary art and boasts breathtaking views of Florence.

An Italian ghost town that fought obscurity, until a mysterious illness brought it to its knees.

A magnificent waterfall is also home to the remains of a Roman hydraulic engineering system.

Crossing this suspension bridge feels like walking through the sky, a fitting tribute to the head of the Apollo program.

This abandoned Brutalist treehouse is a hidden architectural relic.

One of seven Jewish catacombs in Rome and one of only two open to the public.

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

The Pope’s secret escape route.

An Italian hillside ghost town.

Jesus' footprints and the first catacombs in the world.

The oldest volcanology research center in the world.

The old church, buried by the 1784 Mount Vesuvius eruption, is a remarkably well-preserved place where people now pray for the souls of the dead.

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

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

For decades, vendors have sold clothes once worn by American soldiers who stormed Italy in the 1940s.

The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

Venice's "Island of the Mad."

Every day is like Christmas on this street where the traditional Neapolitan nativity scene comes to life.

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

Brass cobblestones mark the places where individual Holocaust victims were taken from their homes.

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

In Rome’s Jewish ghetto, a 200-year-old bakery still makes the neighborhood’s historic sweets.