The world's largest solar furnace uses 10,000 mirrors to concentrate the sun's rays to generate power.

Famed architect Antoni Gaudi built this generous thank you gift to a friendly host who housed him during a job.

This Roman arena once played host to bloody gladiatorial battles.

Museum of amazing old toys and automata.

A Romanesque tower appears when water levels drop.

Super Robot anime statue guards a forgotten suburban development in Tarragona.

Living towers made of people that are now recognized by UNESCO.

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

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

Mountain where Jesus was first tempted by the Devil.

A once grand hotel now sits eerily abandoned in the Catalan countryside outside Barcelona.

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

This cemetery features modernist statues as strange as its name.

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

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

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

A beautiful but toxic fountain of mercury.

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

This colorful statue welcomes visitors to a Barcelona park.

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

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

An open-air "garden" of mural art that changes weekly.

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