A natural arch offers panoramic views of Yangshuo's karst hills.

One of the largest barracks of the Austro-Hungarian monarchy's military is now an abandoned ruin.

The abandoned military base looks like a post-apocalyptic wasteland.

The only natural cave bath in all of Europe.

A UNESCO-protected spiritual seat of the Old Serbian Kingdom and Empire.

In the bowels of a 19th-century brewery lurks a fine-dining restaurant offering an array of themed feasts.

This bridge is so steep it looks like a rollercoaster.

A clear blue swimming hole with hidden caves, still unexplored.

A room in New York City that contains 250 cubic yards of dirt worth a million dollars.

One of the best-preserved Roman amphitheaters is still used today, but for less brutal events.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

A full figure 4th century incorruptible saint lies in a glass coffin in Croatia.

Croatia's towering concrete blossom grows from the site of a World War II concentration camp.

A tower marking the spot where Yugoslavia began its resistance against the invading Nazis stands neglected, but not quite forgotten.

A wunderkammer of gold and silver reliquaries and ancient saintly bones.

This stunning, out-of-the-way Croatian monument commemorates a community's uprising against occupying fascist forces.

Yugoslavia's biggest underground airport lies in ruins.

A wonderfully strange collection of 500+ stuffed frogs doing people things.

One of the largest, oldest, darkest, quietest motel rooms in the world.

In a 345-million-year-old cave that's 200 feet underground, dinner awaits.

An abandoned cemetery lies in ruins as the surrounding forest swallows it whole.

Hidden by the roadside in the Iya Valley, this gem brings together folk monsters and the region's unique geography.

Piled high inside this warehouse and coffee shop are salvaged goods that span every corner of the globe.

For decades these polar bears have roamed all around a Nashville neighborhood.