The Cathedral of St. Ambrose has been hiding a special parishioner within its walls.

This lovely little bridge hidden in a Switzerland gorge is essentially a fairytale.

The ruins of this Dutch castle sit atop a labyrinth of once-secret tunnels and passageways, dating back over 900 years.

One of Hungary's most influential places of learning is also home to one of the world's most beautiful libraries.

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

Inspired by "The Starry Night" this Dutch bike path turns into a glowing work of art each night.

An industrial site turned into Hungary's most cherished natural wonder.

A Belgian self-built tower inspired by the Bible and ancient civilizations.

This centuries-old gothic monster has been converted into a sprawling, glossy bookstore.

An ancient monastery, a locked room, and a mysterious book heist.

A whimsical bridge adorned with decorative dragons.

Martin Bricelj Baraga's monolithic sculpture measures the blueness of the sky, and changes color to match it.

This abandoned Slovenian military barracks has become a punky-political art squat.

A controversial artwork draws attention to the dark history of Prague's "Suicide Bridge."

An enormous and lavish Gothic church in Czechia.

A church of bones, decorated with 40,000 human skeletons.

A museum of alchemy and a basement laboratory all housed in an ancient building in a Gothic tower.

This artificial cave looks like something out of a fairytale.

A fortress built to pacify local uprising that had a stint as a Nazi concentration camp before becoming a five-star hotel.

This tipsy office building in downtown Prague was originally called “Fred and Ginger.”

What looks like a suicide in progress is actually a statue of Sigmund Freud.

The history of occult science is turned into a creepshow at this lurid Prague tourist attraction.

Walk through Czech history in Prague's largest graveyard.

A Jenga-style cylindrical tower of books that appears to go on forever.