A mysterious chasm in the heart of the ancient Roman Forum, the Lacus Curtius was once believed to be a gateway to hell.

A hospital where antique dolls are given new life.

The final resting place of the poets Shelley and Keats.

Ancient snack bar of the Roman Empire re-opened.

Erotic art covers the walls of the largest ancient pleasure palace.

The walls and streets of the ancient city are peppered with penises.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

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

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

The oldest giants in Catalonia are now displayed in a 14th-century Gothic church.

This bustling Italian plaza is built on the ruins of an ancient Roman amphitheater.

Fortified medieval tower house with lovely roof garden.

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.

A slightly creepy gallery of plaster cast models in the same museum as Michelangelo's David.

This private skyway is filled with art and was expanded explicitly so that Hitler could appreciate a river.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

Thousands of narrow alleyways in an ancient medieval city make up what's believed to be the world's largest car-free urban zone.

The other side is actually green.

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

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

The oldest restaurant in the world is this old-world Spanish eatery, still known for its suckling pig.

The world's largest prehistoric copper mine had 30,000 animal bones scattered throughout the maze of passageways.