This old Estonian mine has been kept like a sprawling time capsule of the local shale industry.

This soviet pilot's graveyard is filled with headstones made of airplane fins.

The secret cells in the basement of the KGB's Estonian "Grey House" have been preserved as a grim Cold War museum.

A former imperial sea-fortress and Soviet prison.

Two well-hidden huts let animal lovers spend the night among the bears, wolves, and other predators of the forest.

A decommissioned submarine base makes a great space for graffiti art.

Relics from an era long gone, sit idle outside this Estonian museum.

The entrance to this Frankfurt subway station looks like an old tram car crashed into the concrete sidewalk.

The true meaning behind this sculpture remains unknown.

Atop this electronic store resides a massive fighter jet.

A stick-sprouting statue watching a duo of disembodied dancing deities.

This once-mighty brick factory is now a unique museum experience.

These enormous, stern-faced statues greet visitors with lanterns, and sometimes costumes.

This bed and breakfast is steeped in history and offers guests a unique way to experience nature—glass igloos on a frozen lake.

Finland's northernmost zoo is home to the country's only polar bears.

Fortifications built for a Soviet invasion that never came now sit abandoned in a losing battle against nature.

If you visit Santa's village, you can get your passport stamped to show you crossed into the Arctic Circle.

A small island dotted with old, historic Finnish buildings.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

A subterranean house of worship carved right out of the bedrock.

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

Legend has this precariously placed rock was placed by giants. Science has another explanation.

This fantastical icy castle is built anew every winter.

Elaborate stone houses constructed from the ruins of war.