A lush indoor jungle fills this bustling Madrid transportation hub.

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

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

Abandoned for decades, trains still pass through the now-restored remains of one of Madrid's first metro stations.

Artist Natividad Sánchez wrote a new ending for one of Roman mythology's tragic love stories.

For decades, Puerta del Sol has been illuminated by a giant, guitar-wielding bottle of sherry.

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

The oldest operating roller coaster of its kind, the Montaña Suiza has been thrilling riders since 1928.

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

Two towns are linked by an engineering marvel masquerading as a boring suspension bridge.

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.

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

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

This home designed for chocolate magnate Antoni Amatller is an exquisite treasure-box of Catalan Modernism.

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

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

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

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

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

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

Four-story slides send people whizzing through the math department at this Munich university.

A stairway to heaven, or to nowhere at all.

A subterranean display of public art and architecture.

One of the most easily accessible examples of the rare 1960s UFO houses.