One of the largest caves in the world open to the public.

The Emperor Tiberius' palace of debauchery.

The Roman Emperor's lost summer home and grotto full of enormous sculptures sit along the Italian seashore.

Beautiful views and Roman-style statues on the Italian coast.

A unique Tuscan hideaway acts as an art mecca as well as a hotel.

This immaculate and historic water garden culminates in a massive stone dining table with an inset fountain for chilling the wine of the Cardinal's guests.

Sitting on an Italian hilltop is this surreal fortress built by the mad inventor of electrohomeopathy.

The glowing blue Nymphaeum of Emperor Tiberius.

Geothermal waterfalls in Tuscany.

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

Stalactites and stalagmites in a beautifully lit cave.

Explore the quarry where the marble was sourced for Michaelangelo's David.

A breathtaking flower tunnel bursts with beautiful golden blossoms.

This desert oddity hides in plain sight thanks to a cartographic error and a desert explorer with a punny sense of humor.

This magical and eccentric stepwell is a hidden treasure within the ancient fort city of Mandu.

Romans built the world's tallest artificial waterfall in 271 BC.

Caligula's colossal pleasure ships, discovered by Mussolini only to be lost in flames.

Rome's ancient Etruscan rival, now a park full of ruins.

Jesus' footprints and the first catacombs in the world.

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

2300-year-old Roman road connecting the empire.

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

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

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