Thanks to its heroic service during WWII this Soviet castle has been turned into a monument towered over by a brutalist titan.

Every summer, an open-air swimming pool appears at the base of a Finnish city's beloved winter attraction.

These Finnish rapids have been attracting tourists for over a hundred years and are now released with the push of a button.

Menacing or in memoriam, the Silent People and their meaning are left to interpretation.

Architecturally stunning library serves as the hub of Finnish scholarly life and culture.

This fantastical icy castle is built anew every winter.

Rent out a glass igloo to watch the Northern Lights like you live in the future.

A vast Communist-era exhibition space in the Bulgarian capital.

A spectacular Bulgarian cave resembling a devil's head with a waterfall rushing down its throat.

The ceiling of Prohodna Cave in northern Bulgaria affords a peek at the sky via two deity-sized-eye-shaped holes.

This tiny Bulgarian town offers a stunning location in the mountains and a storied history.

This massive concrete sculpture is said to be the heaviest communist monument on Earth.

Bizarrely shaped rock formations in northwest Bulgaria come with equally bizarre legends.

An architectural marvel that spans the Arda River, and has stories of a haunted past.

An abandoned saucer-shaped monument in the Bulgarian mountains.

Celebrated example of Ottoman architecture that also served as a site for brutal massacres.

A bridge destroyed three times: once as a ruse, then in an actual attack, and finally for the movies.

This top-secret nuclear bunker hidden in a Bosnian mountain has been converted to a modern art exhibition space.

This brutalist monument is inscribed with 9921 names of Yugoslav partisans who perished during WWII.

There's a mini version of Iguazu Falls hidden in the Balkans, and it's got a rope swing.

A war-torn Olympic relic is being overtaken by graffiti and nature.

This museum preserves the hand-dug tunnel that kept Sarajevo afloat during the Serbian siege.

This cluster of little wooden huts once ground local farmers’ wheat into flour during the days of the Austro-Hungarian Empire.

These warring psychedelic crags commemorate an unsuccessful military operation.