A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

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.

Ring the bell to enter a bar that looks equal parts museum and old curiosity shop.

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

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

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

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

Barcelona's historic 19th-century sewers, whose foundations were laid in medieval times, are open to the public for exploring.

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

Mountain where Jesus was first tempted by the Devil.

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

This cemetery features modernist statues as strange as its name.

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.

Rock-hewn monastery complex with hundreds of cave structures tucked away into the mountainside.

Unusual building appears to be haphazardly built from randomly piled bricks.

A cluster of historic bathhouses built on the famed hot springs that gave the Georgian capital its name.

The secret room where early Bolsheviks cranked out propaganda fliers on a smuggled printing press.

You'll find just about anything in this funky Tbilisi flea market.

Bronzes and busts that once stood in the city's main squares are now relegated to a small hidden courtyard.

One of the largest wooden constructions in Europe was meant to be a casino, but soon became an orphanage.

A marvel of Byzantine engineering under the streets of Istanbul.