The Polish capital has had a deep connection to its guardian mermaid for almost a millennium now.

This biographical museum honors the groundbreaking scientist at her birthplace in Warsaw.

A striking public sculpture representing the period of martial law in Communist Poland.

A statue honors the children who fought Nazis in Poland.

A peculiar family mausoleum built by a German nobleman captivated by the occult.

This sprawling concrete suburb of Kraków was designed by the Soviet Union as the model proletarian city.

A huge wooden clock that is so beautiful its creator was forcibly blinded.

A tribute to the Polish insurgents who fought in the failed attempt to end their city's Nazi occupation.

The world’s narrowest house makes for an awkward, four-foot-wide living space.

This man-made mound monument was built out of soil from all across the Polish empire.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

A star-shaped fortress town fort built in the geometric model of the Renaissance utopian city.

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

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

This colorful statue welcomes visitors to a Barcelona park.

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

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

This religious complex carved into a cliff is steeped in legends of miraculous stags and the Holy Grail.

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

Abandoned Nazi train station turned underground astroparticle laboratory.

One of the most spectacular bridges in Spain spans a narrow chasm that divides the city of Ronda.

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

This massive fiberglass Gulliver turns every visitor into a Lilliputian.

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.