A preserved Nazi labor camp now has a Holocaust museum on site and memorials to the thousands that died while imprisoned at the camp.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

A massive playground in the woods of Germany.

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.

This East German military command bunker was ready for World War III.

This enchanting mountain plateau celebrates spooky local folklore.

Retirement home for giant obsolete machines.

The evocative ruins of a medieval village.

This massive steel pyramid can be entered by a set of jagged steps that let visitors stand in its heart.

A UFO-shaped event building originally intended to be a science museum showcasing the future.

Incredible labyrinth of man made caves.

Hiding the longest subterranean river known in the world.

Dedicated to the American general whose reply to a German demand for surrender was simply "Nuts!"

In the heart of Luxembourg's "little Switzerland" weaves a breathtaking natural sandstone canyon with a mythological past.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

Once the local rulers had gone these enchanting ruins housed common folk in an almost real life fairy tale.

This "preacher's pulpit" once used for pagan ritual, is home to a new, and dangerous ritual.

Monuments don't get much more metal than these three giant viking swords planted in a Nordic hill.

This building’s ghostly exterior reflects its former lives as a prison, school, and funeral home.

On the grounds of a former estate in Burgundy stands an elaborate temple that is modeled after the first Tibetan Buddhist monastery.

The history of knife-making in this French city is explored through this museum.

The huge golden reliquary of a testicle-smashing saint.

A floundering Polish shipyard was once the soul of the Solidarity movement that capsized communism.

A huge wooden clock that is so beautiful its creator was forcibly blinded.