A collection of old neon signs from all over Poland line a secluded courtyard.

This centuries-old wooden wonder was built in less than a year and is one of Europe's largest timber-framed churches.

A mysterious structure left behind on the Polish mountainside, sometimes called "Hitler's Stonehenge".

Created as a "model concentration camp" to hide Nazi atrocities from the international community, this former camp-ghetto now holds a museum and memorial honoring the lives lost within.

An Austrian house of bones filled with hundreds of intricately painted skulls.

This cubist Vienna church building looks like some sort of alien stonehenge.

Ugly 18th-century dwarf statues living in a perfectly landscaped Austrian garden.

Terrifically morbid cemetary and site of famous Paracelsus' grave.

The housing complex served as an anti-fascist fortress during the Austrian Civil War.

Artfully arranged bones of 5,800 Austrians.

Double spiral staircases are not unheard of, but they are very rare.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.

Austria's ultra-modern art museum looks like Cthulhu's giant alien heart.

These 12th-century catacombs carved into a mountainside were a place of mysticism and Christian hermitages.

Bizarrely-painted church designed by a controversial artist.

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

Crosses of all shapes, sizes and colors litter the mountain, the site of a huge yearly Orthodox pilgrimage.

Time stands still at this serene burial ground in the center of Budapest.

Budapest's Communist-era statues, banished to the suburbs.

A long spiraling walkway winds through the woods, and around a copper beech tree at the center.

Hitler's bleak vision of relaxation still stands as a mostly abandoned 10,000-room resort complex.

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

Several of these strange cone-shaped bunkers can still be seen around the former Nazi headquarters.

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