This museum preserves the hand-dug tunnel that kept Sarajevo afloat during the Serbian siege.

These warring psychedelic crags commemorate an unsuccessful military operation.

This cluster of little wooden huts once ground local farmers’ wheat into flour during the days of the Austro-Hungarian Empire.

Bridge that died in war and was resurected.

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

The largest Roman amphitheater in the Balkans once held over 20,000 people, but managed to lay hidden for hundreds of years.

According to a local legend, this old castle could only be built after a woman was immured in the walls.

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.

The elliptical citadel resisted the advance of the mighty Ottomans several times, thanks to the military prowess of the "Dragon of Albania."

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

An Albanian monument to the Communism that nearly crushed the country is now a crumbling wreck.

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

A naturally beautiful, seemingly bottomless deep blue spring.

This 700-year-old structure is one of the most unique architectural and historic monuments in Gdańsk.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

An underground city of salt.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

A medieval church built up to defend its village.

Nine centuries-old fortresses guard the walls of this medieval Romanian city.

A fire once nearly devoured this gorgeous 14th-century Gothic cathedral.

Conspiracy theories and occult legends surround this mysterious natural rock formation.

This elaborately decorated, fairytale-like Romanian royal palace is one of the most striking castles in Europe.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."