A floating cat sanctuary on an Amsterdam canal.

The world's only museum devoted to the wonders of fluorescence.

Ancient catacombs form the foundation for this Rococo orgy of a church.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

The stunning interior of this Gothic church is covered in ornate gold details.

In the fictional world of Kcymaerxthaere, celestial wonders marked a portal to a powerful route of travel at this site in Madrid, Spain.

This semi-secret storybook hedge maze is also the oldest garden in the city.

Mountain where Jesus was first tempted by the Devil.

This cemetery features modernist statues as strange as its name.

These secluded and abandoned anti-aircraft defenses have become one the most scenic viewpoints in Barcelona.

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

Step inside the first house designed by Catalan architect Antoni Gaudí, considered to be one of the first Art Nouveau buildings.

The largest Art Nouveau complex in the world is a Barcelona hospital with a 600-year-long history.

One of the most photographed buildings in a city known for its Modernista architecture is an abandoned squat.

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

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

This former Baroque palace on the historic Calle Montcada is a rare architectural gem and was once the meeting place of an aristocratic scholarly society.

Possibly the oldest church in Barcelona, this basilica has its pagan and Christian mythologies all mixed up.

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.