This historic stone bridge has an entire neighborhood clinging to its sides.

Beloved children's TV characters freckle the German city's streets.

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

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

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

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

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

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

One of Antoni Gaudí’s earliest buildings, built between 1886 and 1890 for the industrialist Eusebi Güell.

This amazing example of Valencian Art Nouveau looks more like a cathedral than a public market.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

Spain's largest bullring offers a unique glimpse at architecture and history.

The world's largest wooden structure.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

A display of torture devices used in the Spanish Inquisition and other scourges of medieval Europe.

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

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

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

A pair of gigantic baby heads greet passengers at Atocha Station.

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

A lush indoor jungle fills this bustling Madrid transportation hub.

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

The remains of the second-oldest zoo in Europe can be seen within these library gardens.