An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

The tallest mountain in mainland Netherlands isn't actually very tall.

The underground sanctuary of a mysterious ancient Roman religious cult contains an exquisite traditional fresco.

This Roman amphitheatre was also the location of the first gladiator school.

A town saturated in Italian rationalist architecture was once marshland drained by Mussolini.

This ancient altar emerges from the thick forests to reveal the mysteries of Etruscan sacrificial rituals.

A small house in Tazones, completely covered in shells.

A tiny traditional village keeps an ancient method of beekeeping alive.

A medieval stronghold rising over the ruins of ancient Roman villas along Rome's southern coast.

Micro-nation based around a nine-story high illegally built tower.

An incredible mosaic-lined monument said to have held the remains of an ancient Roman empress.

This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

A medieval, mosaic-lined baptistry built by a heretical Christian sect.

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

The second-highest village in Lazio has attracted artists for 400 years and is now a spectacular open-air art gallery.

Historic fortifications form the boundary of Vatican City, but it’s not entirely surrounded by walls.

A master of trompe-l'oeil creates a stunning, tourist-fooling dome out of a flat ceiling.

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

A detailed pachyderm supports Rome's smallest Egyptian obelisk.

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

Ancient ruins hidden underneath a modern luxury hotel.

Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

This ancient trail climbs the mountain where a Latin League cult worshipped Jupiter, its main deity.