A jaw-dropping "megalibrary" that turns book-browsing into a geometric adventure.

An Aztec snake god has taken the material form of an apartment complex.

In this 400-year-old hotel in Madrid, you'll find a comb in every room, an old clock, and maybe a ghost.

These distorting, funhouse mirrors achieved fame in a renowned piece of Spanish theater.

Not far from Madrid, a set of perfectly preserved trenches date back to the Spanish Civil War.

A subterranean relic of the Spanish Civil War hides below this picturesque park.

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

An ancient Egyptian temple in the middle of Madrid, Spain.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

This mansion oasis contains gardens, sculptures, and fountains just off the busy Plaça Kennedy in Sant Gervasi.

This home designed for chocolate magnate Antoni Amatller is an exquisite treasure-box of Catalan Modernism.

Barcelona's only remaining tram system takes riders to the Tibidabo funicular.

This stunning iron gate designed by Modernist architect Antoni Gaudí is filled with mythic symbolism.

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.

Turntable anonymously received orphans, alms, and groceries.

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

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

Bask in the 19th century grandeur of an eccentric Freemason millionaire's private gardens.

Mountain where Jesus was first tempted by the Devil.

Gaze upon chocolate sculptures depicting everything from chariot races to Gaudí's famous church at this shrine to sweets.

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.

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

Hidden in plain sight on a gable between two towers on the roof of shipping firm F. Laeisz' headquarter in Hamburg sits an unexpected bronze sculpture.