From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

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

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

This Budapest bar allows drinkers to leave their mark on the walls, floor, and even ceiling.

An old asylum graveyard that's been abandoned for half a century attracts those seeking a dark thrill.

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

A steampunk-styled three-floor factory churning out art, activism, and electronic beats.

A collection of anatomical samples from one of the first anthropologists to suggest that humans reached North America by crossing the Bering Strait.

The hidden lair of an alchemist rediscovered in a 2002 flood.

Countless grotesque faces stare out from this eerie Prague art wall.

Around 100,000 bodies are buried below the medieval headstones, many of which mark graves with multiple bodies stacked up to 12 deep.

Two stunning 17th-century libraries and a cabinet of curiosities.

Macabre astrological automaton clock dating to the late 1400s.

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

The most gigantic, swoony, intimidating trio of fingers in all of antiquity.

One man's labor of love, Amman's oldest home has become a time capsule with its doors permanently open to artists and guests.

Death rituals and sacrifice inside a Peruvian megalith.

Keshwa chaca, among the last handwoven Incan bridges, crosses Apurimac Canyon in Peru.

Now containing the bones of the actual conquistador, instead of someone else.

The remains of what was the most important religious complex in coastal Peru for over a millennium.

A market for witches is hidden within a train station.

The mortal remains of an estimated 70,000 people lie in the basement of a monastery in Lima, Peru.

Bold black and white motifs of life and death add a dramatic flair to this 17th-century crypt.

A display of torture devices used in the Spanish Inquisition and other scourges of medieval Europe.