The Renaissance-era courthouse is a relic from the fortified town's centuries of Venetian rule.

Croatia's "hairy stone" fortress is one of the most well preserved Istrian castles.

This military tunnel dates back to World War II and provides visitors with a little wartime adrenaline.

Now abandoned, the world's first torpedo factory is crumbling into the sea.

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

Where the lovelorn find a home for their sentimental keepsakes.

This 135-year-old weather station studied the effects of the climate on human health.

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

One of the largest barracks of the Austro-Hungarian monarchy's military is now an abandoned ruin.

This castle played host to the largest great hall found in medieval Central Europe.

Inside the Šomoška National Nature Reserve exists a unique rock formation rarely seen in the world.

The abandoned military base looks like a post-apocalyptic wasteland.

The remains of an entire Roman city can be explored in this interactive museum.

Hungarian self-built castle.

The abandoned "Red Star Train Graveyard" is the final rusting place for precious artifacts of train history.

A two-way chairlift system between Zugliget and the highest point in the city.

This hidden art nouveau gem was designed by an architect in search of a national style.

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

Museum dedicated to the terror regimes of Hungary.

The oldest private art gallery in all of Hungary.

A museum dedicated to a secret military hospital hidden beneath a castle in Budapest.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

The holes in this wall provide a glimpse into Jewish life in Budapest, both past and present.

A Trabant car, a kangaroo statue, and a plethora of plants take over this abandoned-factory-turned-bar.