A whimsical bridge adorned with decorative dragons.

This one-time health resort was used by aristocrats around the world.

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

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

An underground city of salt.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

The design of this beautifully crafted building was inspired by Norwegian glaciers.

One man's exploration of the human form, including the bizarre and delightful "Man Attacked by Babies."

A dismembered holy head stares out from her beautiful reliquary at the St. Dominic Basilica.

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

The middle finger of modernity.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

The crypts of Capuchin friars decorated with the bones of over 4,000 friars, including an entire "crypt of pelvises."

Medicinal spa created with the discharge from a geothermal energy plant.

If a glacial river suddenly diving into a sheer chasm via a dramatic, multi-stage waterfall isn't peak Iceland, it's certainly close.

Iceland's "Smoky Valley" is a beautiful river that is shrouded in a constant cover of steam clouds.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

This ancient statue of Dionysus lies unfinished and abandoned in one of Greece's oldest quarries.

This black sand beach was crafted from volcanic explosions including the historic Minoan eruption.

Occupied for six centuries by Franciscan Order nuns, this monastery is an amazing ode to Catalán Gothic architecture.

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.

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

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.