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

Street artists transformed this abandoned industrial neighborhood into one of Europe's largest graffiti exhibitions.

A rare surviving Victorian greenhouse designed specifically to house giant water lilies.

An illuminated manuscript comprising the life's work of a lone monk, inexplicably decorated with a portrait of Satan himself.

A fake medieval village in the middle of Turin.

The astonishing collection of an infamous criminologist.

The hidden lair of an alchemist rediscovered in a 2002 flood.

This doorless 20th-century elevator doesn't stop or slow down.

A Jenga-style cylindrical tower of books that appears to go on forever.

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

Street artists transformed an abandoned air vent into the beloved Star Wars robot.

Where once there was a train station bathroom, there is now this German burger joint.

A collection of abandoned typographic signs from Berlin and beyond.

A surreal museum of extraordinary industrial objects.

The most visited, and possibly most controversial, museum in Germany.

A slice of central Asia in the middle of Berlin.

Started as a kitchen garden, now the second largest botanical garden in the world.

An eerie, derelict amusement park in Berlin.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

A tower-like theater in the Swiss Alps built to withstand the high winds and avalanches of the mountain pass.

The abandoned "Ghost Mansion" was left to decay in the mountains of Northern Italy.

Nestled in the hills of Tuscany are gorgeous, multicolored hot springs.

Eighteen mummies have stood guard behind the altar of this tiny church since 1833.

This 21st century cabinet of curiosities includes dinosaur bones, moon rocks, film memorabilia, and more.