The morbid items in this small and hidden museum are not for the weak stomached.

Building owners can take out tiles for free at this repository for historic building materials.

This museum is home to one of the biggest collections of printing press technology—plus a river view.

An underground paleo-Christian burial site composed of the remains of several cemeteries and Basilicas.

A lush indoor jungle fills this bustling Madrid transportation hub.

This grubby wall is said to be one of the Earth's esoteric energy centers.

At first glance, this area seems like just another city park, but the lush landscape hides a dark past.

The unsettling remnants of a torn down movie set lies nearby the ruined location of the actual Płaszów Labor Camp.

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

The stunning interior of this Gothic church is covered in ornate gold details.

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

A spherical "micro-nation" in the heart of Vienna.

A relic of the Cold War tucked away in the forested hills above Bratislava.

Thousands of slain Soviet soldiers are buried within the shadow of this enormous obelisk.

A line of disused military bunkers built to defend against Nazi invasion lies hidden on the outskirts of the city.

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.

Walk through Czech history in Prague's largest graveyard.

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

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

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

Ancient catacombs form the foundation for this Rococo orgy of a church.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

The only urban monument in the world designed by the great surrealist painter Salvador Dalí.