Stone memorial that's said to predict the death of the pope and the site of the Cadaver Synod.

The ruins of this gorgeous clifftop castle look like something from a fantasy novel.

A tribute to an iconic act of defiance from the Croatian War of Independence involving a small car.

The only gulag ever to exist in socialist Yugoslavia.

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

Where the lovelorn find a home for their sentimental keepsakes.

A musical instrument played by the sea.

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

An ethereal glowing blue ocean cave in Croatia.

A 90-ton, gravity-defiant steam locomotive shoots for the skies in this bizarrely beautiful public artwork.

There are thousands of tributes and memorials to the King, but none quite like this one in a Kraków city park.

These massive moving sand dunes have swallowed an entire village and are still on the run.

Communism's topsy-turvy effect on Poland has been brought to life in this wacky tourist trap.

This uber-quaint Polish village is known for its habit of painting elaborate floral motifs on just about everything.

The site of the first battle of World War II.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

Real bones which are said to have belonged to a Polish dragon.

An underground city of salt.

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

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

A celebration of all things tacky, garish, and bizarrely creative in the Romanian capital.

The entrance to this Frankfurt subway station looks like an old tram car crashed into the concrete sidewalk.

There are two dozen tanks just sitting in an open field in Lower Saxony.