Inside this small chapel tucked away in the forest is one of the most well-preserved Danse Macabre frescos.

Trimmed trees grow alongside the graves like topiary tombstones.

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

This beautiful Croatian fortress is haunted by legends of forbidden love.

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

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

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

When a supermarket opened up shop within a medieval building it became protected by UNESCO on a technicality.

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

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

This picturesque medieval monastery guards a small trove of historic treasures.

This scale model of our solar system hid in plain sight for years before a physics team sought out all the planets.

This former estate of a fascist leader is now a burnt out ruin leading to a system of secret tunnels.

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

Once a state-of-the-art tuberculosis treatment spa, these ruins are now ruled by paintball players.

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

An ethereal glowing blue ocean cave in Croatia.

An autonomous republic of Orthodox monks.

A fitting attraction for the corn capital of the world.

Crumbling necropolis set high above Fez.

Heralded as the world's first theater, these ruins are often overlooked as they reside in the shadows of the Acropolis.

The other side is actually green.

The courtyard of this small Marinid madrasa is a dazzling example of intricate Islamic architecture.

Traditional 11th-century outdoor tannery.