A national collection of Communist-era musical posters.

An impressive monument to Poland's independence.

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

The world’s narrowest house makes for an awkward, four-foot-wide living space.

The NASA scientists behind Apollo 11 started out developing Nazi weapons at this abandoned German rocket factory.

This open-air museum was originally a World War II testing ground for German missiles and rockets.

Old cabin-like homes in a rural community untouched by time are known for their vibrant and colorful window shutters.

The largest toy museum in Poland showcases Europe's history of childhood.

The site of the first battle of World War II.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

Medieval Danse Macabre Fresco in Northern Brittany.

This abandoned coliseum was intended to be a grand Nazi rallying ground before it was halted at the end of the war.