Spanning the El Chorro gorge, this pathway used to be one of the most dangerous crossings in the world.

Rare karst landscape eroded from a flat seabed.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

A museum dedicated to the centuries-old cave dwellings that housed marginalized communities on the outskirts of the former capital of Muslim Spain.

A large statue of Pope Gregory XIII in Bologna was disguised as Saint Petronius to avoid destruction.

A striking memorial recalls thousands of Bolognese men and women killed fighting fascists in World War II.

Legend has it this fountain built to symbolize the Pope’s power hides a strange secret concerning Neptune's manliness.

The remains of an ancient Roman city are hidden underneath Bologna's beautiful public library.

A massive line that stretches across the floor of Bologna’s largest church was created by a 17th-century scientist to measure the movements of the Sun.

In the world's oldest university is a stunning 17th century anatomical theater carved from spruce.

A diverse collection of wax, bone, papier-maché and mummified relics.

Over 100 towers were built in Bologna during the Middle Ages, but only 22 survive.

Stuck in the arcade of Casa Isolani are three arrows of mysterious origins.

A small window on Via Piella offers a lovely and rare peek at Bologna's lost canals.

Time has been frozen at this station since the bombing in 1980—or so it was believed.

A popular legend claims that the famous pizza was invented at a restaurant in this alley.

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

A labyrinth of ancient tunnels hidden below the city holds the ruins of 2,500 years of history.

Wander through the Corridor of Wonders in these stunning limestone caverns.

A 1,000-year-old church holds the bones of the Christian martyrs who died hiding inside it.

A long-buried ancient ruin unearthed right in the middle of the city.

Also known as the Temple of Poseidon, this is one of the best-preserved Greek temples in the world.

The only visible remains of this ancient Greek underground temple is its roof protruding from the earth.

Geometry and mystery come together in an epic show of octagonal masonry.