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

This is the oldest Roman-made bridge in the city still existing in its original state.

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

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

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.

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

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

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

Medieval town turned hippie commune, once home to the secret foreskin of Jesus Christ.

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

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

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

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

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.

This ancient Roman prison is decorated with an upside-down cross not as blasphemy but as saintly tribute.

More sculpture than building, this architecturally significant temple was built on the spot of Saint Peter's crucifixion.

A huge enchanting public park just outside the ancient walls of Rome.

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

Installed in an act of one-upsmanship, the annual sundial in this church is also a symbolic victory for the Gregorian calendar.

This Roman arch marks the location of an ancient gate at one of the Seven Hills of Rome.

This bronze boar's snout has been rubbed to a golden sheen by visitors seeking good fortune.

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