In the hinterlands of Serbia's capital, a giant reflective mushroom houses an aeronautical history of the former Yugoslav republic.

Not far from a popular beach, an unfinished, abandoned mansion for Bulgaria's last communist dictator.

Small church on top of a huge rock column.

An enormous Soviet aircraft, the only one of its kind, stands at the deserted shore of the Caspian Sea.

Abandoned medieval hill town.

This mountain trail inspired Nietzsche to complete his magnum opus.

This ancient Roman bridge and aqueduct still stands as a wonder of classical construction.

Bell tower juts out from a village buried under a lake.

One of the highest mountain passes in Europe has been ranked among the best driving roads in the world.

These delicate sand pyramids look like naturally occurring gothic spires.

A climbing route in the mountains of Italy’s Dolomites, built for soldiers during World War I.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

This top-secret nuclear bunker hidden in a Bosnian mountain has been converted to a modern art exhibition space.

There's a mini version of Iguazu Falls hidden in the Balkans, and it's got a rope swing.

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

The remains of a military communications outpost still stand on this Greek island.

The ruins of this monumental city founded by the first Roman Emperor are strangely overlooked by most travelers.

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

One of the largest single-span stone-arch bridges in the Balkans looks like something straight out of a fairytale.

Local lore says two enemy dragons live within these breathtaking mountain lakes.

This 13th-century monastery chiseled into the side of a mountain is equipped with a bridge that can be lifted to protect against raids.

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

A naturally beautiful, seemingly bottomless deep blue spring.

A medieval bridge stretches over a sulfur-rich river that leads to year-round natural hot springs.