An ossuary built in 1210 to collect bones from the Ospedale Maggiore of Milan.

A statue in the heart of Edinburgh honors a bear that served in the Polish military during World War II.

J.R.R Tolkien, C.S. Lewis, and other "Inklings" met at the Oxford pub to discuss the now legendary fantasy stories they were writing.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

Stockholm's decidedly unique public transit system has doubled as the world's longest art gallery for decades.

This Communist-era residential block is one of the longest residential building in Europe.

This fairytale medieval church in Poland originally spent centuries in Norway.

Boats must transform into railroad cars to navigate this Polish canal.

A collection of old neon signs from all over Poland line a secluded courtyard.

This centuries-old wooden wonder was built in less than a year and is one of Europe's largest timber-framed churches.

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

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

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

In the summer, the area around this sculpture transforms into a vibrant concert venue.

This extensive collection covers thousands of years of Polish military history.

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

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

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

A menacing statue of this mythical creature can be seen at the legendary site of the monster's lair.

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

Catacombs turned marketplace.

An exercise in radical design and social living that became the epicenter of Soviet spy networks in London.

William Blake claimed to have painted this gothic masterpiece after encountering this nightmarish being in a vision.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.