Rare karst landscape eroded from a flat seabed.

A New York–based physician returned home to Spain to build his own elaborate monument to Christopher Columbus.

This art installation at an abandoned lipstick factory has distinct anti-capitalist vibes.

This cemetery features modernist statues as strange as its name.

A once-secret library of Freemason history in Catalonia.

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.

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

These 2000 year old remains of a Roman aqueduct are hidden inside a hotel lobby.

This cafe offers a curated collection of treats and tipples made by monks and nuns.

This fountain was designed to honor the man who helped bring water to Barcelona.

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

A beautiful but toxic fountain of mercury.

A bookstore dedicated to the intersection of comedy and art.

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

A surrealist labyrinth and museum of contemporary sculptures.

Occupied for six centuries by Franciscan Order nuns, this monastery is an amazing ode to Catalán Gothic architecture.

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

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

One of Europe's largest supercomputers is housed inside of a disused chapel.

The abandoned ruins of a beautiful medieval castle just outside Barcelona.

Hidden well off the beaten path in Catalonia is this crumbling medieval castle that is slowly being covered in graffiti.

A local artist created this giant rippling wave.

Built on the foundations of an ancient Roman villa, the unique architecture of this castle on the Catalan coast was used as a set for 'Game of Thrones.'

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