Built to give thanks for the passing of a plague epidemic, this cathedral is a one-of-a-kind architectural hybrid.

Op-art architecture designed for happiness.

The topiary maze at the Habsburg hunting lodge.

The crypt of the imposing Stephensdom holds royal intestines and thousands of skeletons.

Built to repay the sins of the father, this church is home to one of the most valuable works of Western art.

Ancient snack bar of the Roman Empire re-opened.

Go inside to really appreciate this 500-year-old technological masterpiece.

Pilgrimage site for star-crossed lovers.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

A large grotto built in the 16th century amidst Florence's famous Boboli gardens.

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

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.

Teeny tiny hotel on the coast of the Canary Islands.

A 16th-century Andalusian palace.

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

This Canary island is a quintessential example of nature’s beauty, and its unbridled fury.

An impressive display of ships and artifacts from the ancient Mediterranean maritime trade.

Hundreds of caves once used to store grains and animal feed.

The oldest Roman lighthouse still in use.

The world's largest wooden structure.

The chefs at El Diablo use heat generated by an active volcano to cook the food.

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.

The final resting place of the great navigator, or maybe his brother.

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