Italian cave with exceptional acoustics and an unsavory history.

Erotic art covers the walls of the largest ancient pleasure palace.

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

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

Two very green residential towers cleaning the air in one of Europe's most polluted cities.

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

An ancient artistic garden parlor full of hidden water wonders.

Ancient ruins hidden underneath a modern luxury hotel.

Venice's island of the dead.

This picturesque Umbrian city has a subterranean side that has long remained hidden.

Ancient snack bar of the Roman Empire re-opened.

The world's most active stratovolcano is almost always erupting.

100 year tradition of fist fights, marked by marble footsteps.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

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

This hydrochronometer was invented by a Dominican monk and is a prime feature in this garden.

The "Great Sewer" of ancient Rome is one of the oldest sewer systems in the world, and is still in use.

Those who own or stay at this 500-year-old, allegedly cursed house often meet terrible fates.

This ancient market is often referred to as the oldest shopping mall in the world.

The secret medieval communication system will whisk your words above the noise of the crowd.

A sinister pyramid in the Frari contains the heart of the famous neoclassical sculptor.

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

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

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