Legions of Roman soldiers bathed in this ancient spa complex under a Budapest transit station.

This hidden art nouveau gem was designed by an architect in search of a national style.

The mummified right fist of a 1,000-year-old saint-king sits inside an ornate golden reliquary.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

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

A former steam-powered mill from the 1800s is now an industrial park with a giant steel dragon slide.

Mountain where Jesus was first tempted by the Devil.

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.

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

A massive 1830s industrial site once known as Czechia's "Iron Heart" has been transformed into a playground of science, technology, and art.