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.

Elaborate tile work in this railway station tells the story of Portugal.

A hidden three-foot-wide house separates these two regal churches.

Eighty million natural history specimens call this gargantuan museum home.

Kings Cross Station pays tribute to its role in Britain's best-selling book series.

Stunning Roman aqueduct used for 1900 years and still standing.

Replica of Seville, Spains famous Giralda, a former minaret converted into a bell tower.

Holy Grotto of Montserrat Monastery holds one of Europe's mysterious black Madonnas.

The Gaudí-inspired building that was the start of Terrassenc modernism.

A gravity-defying "devil's bridge" that has a surprising architectural feature for its stability.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

The 2,000-year-old Roman columns are hidden within Barcelona's Gothic Quarter.

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

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

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

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.

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

Catalonia Tradition: Beating the hollow Christmas log until it defecates in your fireplace.

Week-long block party becomes a competition for the best decorated street.

This cemetery features modernist statues as strange as its name.

Mountain where Jesus was first tempted by the Devil.

A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

A science fiction-inspired apartment building designed by a famous Spanish architect.