This Roman arena once played host to bloody gladiatorial battles.

Long tunnels run under the ancient chariot racing circuit to the tower.

Stunning Roman aqueduct used for 1900 years and still standing.

A centuries-old bar once frequented by Picasso, Hemingway, and Dalí.

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

Turntable anonymously received orphans, alms, and groceries.

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

A beautiful but toxic fountain of mercury.

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

A program of Communist glamour in post-Stalin Poland is preserved in this colorful museum.

These 18th-century paintings of Warsaw were used to reconstruct the city after World War II.

An artificial date palm stands as a memorial to Warsaw's Jewish community.

Hundreds of notes give thanks to the patron saint of lost causes.

The giant statue and its model solar system honor the native Pole who declared that the Earth revolves around the Sun.

Special benches that play Chopin's music are scattered throughout his native city.

After the famous composer died in Paris, his sister snuck his heart out of the country to honor his wish that it be buried in their native country.

One of the world's largest collections of medieval religious art.

These plaques found across Warsaw commemorate the sites where executions or battles took place during the German occupation.

This bell stars in a tragic love tale and is said to make wishes come true.

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

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

A dramatic sculpture high up in Yorkshire with vistas on an industrial scale.

Astonishing rock formations dot the Brimham Moor landscape.

Harry Potter once visited this massive limestone cliff, which was carved by an ancient glacial river.