Double spiral staircases are not unheard of, but they are very rare.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

The world's largest historic armory was established by independent citizens to defend themselves from the wars of larger forces.

This ominous Albanian fortress houses tanks and downed planes as a reminder of their victories over Western imperialism.

Once the fallout shelter of a dictator, this sprawling bunker is now a combined history museum and contemporary art gallery.

Hundreds of thousands of concrete bunkers crowd Albania long after the fall of Communism.

This 3,800-year-old site contains markers used to study the movement of the sun and moon and create a lunar calendar.

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

This military tunnel dates back to World War II and provides visitors with a little wartime adrenaline.

Now abandoned, the world's first torpedo factory is crumbling into the sea.

The remains of a sunken military ship wreck visible through clear water.

The only gulag ever to exist in socialist Yugoslavia.

Just a few miles from Novalja, a strange geological oddity has left scientists baffled.

Former military fort and site of untold horrors during WWII, this island may become the Adriatic's next luxury resort.

A tiny church on a man-made island in the Adriatic.

A curious cave church carved into the face of a cliff.

What started as a collection of vintage tractors turned into a museum filled with cars, radios, and other oddities.

This natural spa is known for its healing properties and vibrant hue.

This dazzling Art Nouveau mansion is now home to the Modern Art Gallery Subotica.

Religious perseverance and cultural coexistence manifest in an architectural gem that multiple wars couldn't topple.

An abandoned monument remembering the "Pančevo Holocaust" now stands as a shadow of its former self.

It may seem a little out of place in a tiny village, but the inspiring story of its creation made headlines.

Despite being pillaged and destroyed a number over times down the centuries, this historic church still sort of stands.

A Serbian church lit by chandeliers made of weapons.