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

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

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

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

Macabre astrological automaton clock dating to the late 1400s.

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

Colorful concentric circles honor a small Croatian town's supposed spot at the nucleus of it all.

An eclectic art form practiced by untrained masters is celebrated at this museum in the heart of Zagreb's old Upper Town.

Island wonderland for communist autocrats.

This Croatian fairytale castle is slowly falling apart thanks to years of neglect.

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

A musical instrument played by the sea.

Sofia's legislative center is continuously reinventing itself.

A vast Communist-era exhibition space in the Bulgarian capital.

"Holy Wisdom" overlooks the city that became its namesake.

A striking symbol of the Bulgarian capital.

This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.

This historic black and white monastery is one of Bulgaria's architectural jewels.

Inat Kuća, or "House of Spite," is more than just an oddly named restaurant.

This historic timepiece is thought to be the only public clock in the world that keeps lunar time.

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

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 historic cemetery was inaccessible for several years due to dozens of land mines.