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

This truly palatial work of Communist-era architecture now sits crumbling on a Croatian beach.

Gargoyle head that brings good luck.

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

Where the lovelorn find a home for their sentimental keepsakes.

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.

Macabre astrological automaton clock dating to the late 1400s.

Humble beginnings for one of the world's most famous scientists.

Longest fortress system anywhere in Europe.

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

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