This ancient Spanish castle sits high upon a hilltop.

This magical space partly designed by Antoni Gaudi is one of the best examples of romantic gardening in the Mediterranean.

A completely underwater art museum sends a stark message about humans' impact on the environment.

At the foot of a waterfall lies a peaceful swimming lagoon and evidence of over 60,000 years of human habitation.

Bask in the 19th century grandeur of an eccentric Freemason millionaire's private gardens.

Wonderland replication in progress by one persistent man.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

This cemetery features modernist statues as strange as its name.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Three bridges and one giant canyon make up this fantastic Spanish settlement.

Hidden beneath the famous St. Peter's Basilica is a veritable city of the dead that may hold the remains of St. Peter himself.

This shining multicolored metro station deep under Naples is said to be the most beautiful in Europe.

A once-luxurious, now abandoned hotel in the Italian Alps.

Crossing this suspension bridge feels like walking through the sky, a fitting tribute to the head of the Apollo program.

The world's most active stratovolcano is almost always erupting.

Secret refuge and museum of the Duke of Florence.

This palatial spiral staircase was so unusual the name "snail" was given to the noble family who built it.

Dramatic sea stacks adorn the coast of this small village on the Adriatic coast.

Walk through a fairytale in Tuscany.

A sunken idol welcomes parishioners to Davy Jones' Locker.

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

One of several skulls claiming to belong to the beheaded St. John the Baptist is on display at this Roman church.

Pilgrimage site for star-crossed lovers.

This sword isn't waiting for a king to pull it out. It was placed there by a saint.