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

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

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

Five million people are laid to rest here, more than the population of Madrid itself.

Elaborately carved to showcase the glorious wealth that the age of exploration brought to the Portuguese empire.

One of the world's oldest universities houses an incredible collection of anatomical models, mummified body parts, and human bones.

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

18th century anatomical amphitheater of the Royal College of Surgery of Barcelona.

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

The oldest giants in Catalonia are now displayed in a 14th-century Gothic church.

The morbid items in this small and hidden museum are not for the weak stomached.

This funky former tobacco factory is one of the most striking examples of Madrid's cultural diversity.

This amazing abuela became a diehard metal fan late in life and an icon of Madrid's '80s rock scene.

Commonly acknowledged as the only public monument to the Devil himself.

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

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

This cemetery features modernist statues as strange as its name.

Mountain where Jesus was first tempted by the Devil.

Catacombs turned marketplace.

This artist's home turned gallery/museum preserves the creator's love of "Eastern" influences.

A Victorian park cemetery, standing on the site of what was once the Great North Wood.

This wildly-tiled artist's palace is a living and growing account of the creator's life, loves, and labors.

The final resting place to 300 Victorian-era pets hides inside the city park.

The remains of Crystal Palace Great Exhibition of 1851.