There was a top secret plan during World War II to seal a group of soldiers inside the rock.

The ghost town where the villagers refuse to leave.

The world's most delightful not-NOT-religion welcomes visitors to the town of Templin, just like its more stoic peers.

Museum dedicated to "the man who moved the Earth."

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

The two abandoned overpasses are among the largest bridges in Poland.

A peculiar family mausoleum built by a German nobleman captivated by the occult.

This fairytale inspired, warped building houses restaurants, shops, and a radio station.

A miniatures park with a model of Wolf's Lair as it looked during World War II.

This hilltop ruin is of the hundreds of stone columns built in tribute to the first German chancellor.

Built to transport German U-boats through the never-completed Masurian Canal, the locks near this Polish village are now home to a rope course.

This remote church calls a tiny island its sanctuary.

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

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."

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

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

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 now-defunct synthetic fuel plant was once a major cog in the Nazi war machine.

On this Polish road, an optical illusion makes cars seem to roll uphill.

A small granite monument marks where the borders of three countries meet.

A monument to Poland's famous alleged UFO abduction case.

This 13th century Gothic brick castle is the largest in the world by surface area.