This 135-year-old weather station studied the effects of the climate on human health.

A World War II evacuation tunnel turned into a history display of Croatian state and people.

A peculiar museum that includes many drunken tales, a drunk driving simulator, and much more.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

This former estate of a fascist leader is now a burnt out ruin leading to a system of secret tunnels.

Once a state-of-the-art tuberculosis treatment spa, these ruins are now ruled by paintball players.

Where the lovelorn find a home for their sentimental keepsakes.

This cave at the base of an unusually shaped cliff is said to be inhabited by a mythical forest enchantres from Scandinavian folklore.

A mysterious stone staircase deep in the Swedish woods, said to have been made by trolls.

A century-old fort from Stockholm’s “Sausage Line” defenses.

Deep in the Swedish forest hides a forgotten water-powered carousel.

This red light district plaza memorializes the Fab Four and their historic connection to the area.

A mammoth WWII anti-air defense tower has been repurposed as a hotel with a rooftop garden.

One of the largest legal spray spots in Hamburg.

This dockworkers' lunch joint has been left leaning by a century of storm floods.

This contentious squat has stood through fire, violence, and government intervention as a hotbed of leftist protest.

A wunderkammer of exoticism immortalized by Tom Waits.

Hamburgers are intensely proud of their tunnel beneath the river.

Once the tallest building in the world, this abandoned church is now a monument to the destruction of WWII.

Northern Europe’s largest castle ruins sit precariously on an island cliffside.

Local legend says a monk brought Christianity to Bornholm through his sermons in a cave inside this free-standing rock.

A whimsical sculpture garden right out of a children's storybook.

The largest of Denmark's seven mysterious round churches stands on an island in the Baltic Sea.

World War II Soviet Russian soldiers were buried on the Danish island after the war had ended.