A 2,000-year-old engineering wonder hides beneath an Italian town.

The sunlight passing through the opening of this huge cave system creates a magical effect.

Buried next to Pompeii, this lesser-known Roman villa was the opulent vacation home of Emperor Nero's wife.

Deceased nuns were placed on stone chairs to decompose, while the surviving nuns prayed near the lifeless bodies.

This church carved into the rocks is full of enchanting stone statues.

This one-of-a-kind archeological site is home to strange prehistoric ruins, the original use of which is still a mystery.

This amazingly preserved Doric temple was abandoned before it was ever completed.

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

This overgrown mountain village has been abandoned for nearly a century.

The ruins of an abbey believed to have been founded by Charlemagne in the 9th century.

The only visible reminders of an elaborate engineering project that kept the tower from reaching the tipping point.

This breathtaking monastery was established by Saint Benedict himself 1,500 years ago.

A dreamlike medieval church dug into the tuff rock, with unusual carvings and possible traces of the Templar knights.

One of the most important yet well-hidden museums dedicated to the history of medicine.

An abandoned 17th-century baroque hunting lodge with a wonderfully strange architectural plan.

A magnificent Neogothic tomb hides within this Italian fairytale-like forest.

An eccentric home in Sicily turns heads on a regular basis.

This Arabesque Italian castle was built with a primitive, if ingenious, air-conditioning system.

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

Ancient cave tombs known as the "houses of fairies."

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

Haunting graffiti left by prisoners of the Spanish Inquisition.

A beautifully well-preserved ancient Roman villa.

What looks like a link in Gondor's early warning system is actually a centuries-old Italian fortress.