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

The leathery remains of a woman who died in the 13th century now lie in a church named for her.

This tile-work piece featuring a chicken riding in carriage is both a remarkable artistic creation and a social commentary of politics and culture in 17th-century Portugal.

Eat the ultimate iteration of Portugal's most beloved pastry.

At night, bats patrol this magnificent 18th-century space in search of book-eating pests.

2300-year-old Roman road connecting the empire.

A collection of objects supposedly singed by the hands of souls in purgatory.

Plaques on its facade commemorate the Tiber's most destructive deluges.

The remains of this 2nd-century Roman temple are incorporated into a modern building.

A monumental fountain in Rome features a large statue of Moses that has been criticized for centuries.

The martyr's wax-enhanced skeletal remains lie preserved in a glass case in the Santa Maria della Vittoria in Rome.

An ancient Egyptian obelisk is now used to commemorate fallen Italian soldiers.

A sculpture serving as an homage to Pope John Paul II.

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

An ancient Roman temple first dedicated to an emperor's wife is now a church.

This one-of-a-kind Roman arch is not actually dedicated to the god Janus.

This ancient Roman arch misled treasure hunters for centuries.

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

This small church was constructed over the ruins of three temples dating to the Roman Republic.

This small, ancient Roman temple was once a church dedicated to the patron saint of penitents.

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

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

The only remaining arch of the oldest stone bridge in Rome stands in the middle of the Tiber.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.