This piece of early engineering is rather unknown despite its location in the heart of Madrid.

This underground church is topped with a 500-foot cross that is seen by many as a beacon of fascist hubris.

This influential Renaissance-era library was once the haunt of kings and monks.

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

A must for film lovers in Madrid and home to the Spanish Film Library's projection space.

The Cathedral of Salamanca has a number of unusual carvings but none so surprising as a modern astronaut.

This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

This postmodern apartment block was designed to be a vertical neighborhood.

This unassuming bookstore in the heart of Madrid is one of the oldest in Spain.

Cliffside houses provide a spectacular view from their perch above the valley.

A giant hand emerging from the ground beckons visitors into a park in Madrid.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

Among the oldest structures in Madrid, these Moorish walls once guarded the medieval city of Mayrit.

A vista of the city and sea from atop the little-known viewing deck on an unassuming Columbus statue.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

This stunning iron gate designed by Modernist architect Antoni Gaudí is filled with mythic symbolism.

The iconic boulevard is the perfect place to catch sight of a bicycling skeleton, a levitating Satan, or a chef with his head stuck in a pizza.

These magnificent city walls rise from the barren sun-baked Spanish plains like something straight out of a fairytale.

Over two centuries old and counting, Madrid's massive botanical garden contains one of Europe's only desert environments.

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.

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

A lush indoor jungle fills this bustling Madrid transportation hub.

Construction of Barcelona’s iconic (but controversial) church was finally completed in 2026—a century after the death of its architect.

Giant topiary dog once played a role in a terrorist bomb plot.