Macabre symbols of death and mummies on display set the tone of this Italian purgatory church.

A naturally beautiful, seemingly bottomless deep blue spring.

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

This exclusive resort has completely covered a tiny Balkan island in a 5-star warren of guest rooms.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

This abandoned airplane hanger is said to have once been a top secret launch facility.

Yugoslavia's biggest underground airport lies in ruins.

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

Now harmless, this looming post struck fear into the heart of medieval troublemakers.

A closer look at this somewhat faded hotel by the Corinth Canal reveals the architectural undertones of a genius.

The only gulag ever to exist in socialist Yugoslavia.

This truly palatial work of Communist-era architecture now sits crumbling on a Croatian beach.

Between Neo-Pagans and Neo-Nazis, these strange rock formations have a curious cult following and a very strange history.

The industrial monstrosity known as Bagger 258 is a colossal mining machine built in the DDR - but now left for dead in a German field.

It's always summer at the beach inside this former airship hangar.

A tour of underground Berlin takes you through WWII air raid shelters and tunnels used to smuggle people out of East Germany.

Super-heavy Nazi architectural experiment.

The ruined remains of the airport Claus von Stauffenberg departed in his failed attempt to kill Adolf Hitler.

A sprawling Baroque park with 300-year-old hydro-pneumatic waterworks.

A Saxony castle houses one of the largest and most outstanding mineral collections in the world.

These beautiful objects represent beautiful ideas.

"The most colorful grottoes of the world.

Terrifying derelict military hospital once housed a recuperating Hitler.

This incredible stone temple is a monument to death, victory, and fantasy architecture.