A hidden art gallery in an abandoned Warsaw fort.

The 700-year-old fortress was the site of Count Orlok's castle in "Nosferatu."

A massive 1830s industrial site once known as Czechia's "Iron Heart" has been transformed into a playground of science, technology, and art.

The mystery of the Putim Ossuary involves a tricorn hat.

This network of conjoined cellars was riddled with traps and supposedly allowed the townspeople to pretend their homes were deserted.

These 17th-century mummies are no longer naturally preserved, but remain on display today.

Mysterious painted skulls in Moravia.

The oldest garden in Prague, once part of an medieval orchard.

Enormous sandstone towers loom within a Czech forest.

The deepest sinkhole in Central Europe comes with a grisly tale and an unusual nickname: “The Stepmother Abyss.”

Mummified monks and the accidentally interred, in a 17th-century crypt.

An Orwellian sculpture with eyeball cameras watches passersby.

Thirty creepy ghosts now inhabit this decaying 14th-century church.

Two monstrous faces loom over a village in Czechia.

Europe's second largest ossuary wasn't discovered until 2001.

Underneath this small church are 15,000 bones, arranged by an obsessive academic.

The risqué mixed-media sculptures are supposedly a metaphor for Czech politics.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

The birthplace of an eccentric alchemist and possible inspiration for the fictional reanimator of monsters.

The fairy tale castle of the "fairy-tale king."

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

Amsterdam's Red Light District leaves little to the imagination.

This museum inside Amsterdam's largest cemetery explores how people deal with death.

A Portuguese Jewish cemetery filled with stunning grave monuments that date back to 1614.