This ancient hydrological marvel is now the base of a modern outdoor cinema.

An ancient octagonal weather station named for the eight Greek gods of wind.

This former military installation was turned into a discipline center by the Taiwanese Navy.

An early 20th-century bullring converted into a modern shopping center.

This colorful statue welcomes visitors to a Barcelona park.

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

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

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

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

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

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

Turntable anonymously received orphans, alms, and groceries.

An unusual stroll through gentlemen's erotica demonstrates that pornography is timeless.

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

A temple to modernity, tucked away amid Barcelona's more well known museums.

This former medieval prison now unlocks Estonia’s rich photographic history.

A church filled with the bones of hundreds of virgins martyrs—or so they say.

A rare chance to ride one of the few continuous elevators still in operation.

This tremendous timepiece was once the largest cuckoo clock in the world.

The final resting place of the famed German pilot, the "Red Baron."

The entrance to this Frankfurt subway station looks like an old tram car crashed into the concrete sidewalk.

Bangkok's men with dangerous jobs come here in search of protective talismans.

A treasure trove of pathological, forensic, parasitological, and anatomical specimens.

A shrine honoring a legendary ghost bride lies within this vibrant temple.