Synagogue built from the stones of Solomon's temple contains the golem of Prague.

This automated sculpture of two men peeing will spell out text messages with their micturition.

An eerie, existential museum dedicated to the author of "The Metamorphosis."

A mocking tribute to the past and modern leadership of Prague.

This Prague museum collects brutalist relics and memories from the country's former Soviet rule.

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

Macabre astrological automaton clock dating to the late 1400s.

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

The big toe of this towering monument to a Croatian national hero is worn from years of superstitious rubbing.

Now harmless, this looming post struck fear into the heart of medieval troublemakers.

Island wonderland for communist autocrats.

Formerly Yugoslavia's "forbidden island," this sleepy little city still holds the abandoned remains of military strongholds.

Large, airy hallways hide within an impenetrable fortress that beckons urban explorers.

A musical instrument played by the sea.

A chain of 16 wondrous lakes formed as a result of the gradual dissolution of soluble layers of bedrock.

An ethereal glowing blue ocean cave in Croatia.

An homage to the medieval rulers of Bulgaria.

A field filled with carved medieval tombstones called stećak.

The remains of the last Bosnian fortress to fall to the Ottomans are still standing.

Controversial site of what could be Europe's first pyramid.

This ironic war memorial thumbs its nose at a campaign of inedible humanitarian aid food products.

Celebrated example of Ottoman architecture that also served as a site for brutal massacres.

A number of craters left by fatal mortar strikes have been filled with red resin to remember those lost during the Siege of Sarajevo.

This surreal memorial/cemetery is a necropolis of crumbling stonework and puzzle-shaped headstones.