This huge metal monument is slowly being stripped to its concrete skeleton.

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

The remains of a sunken military ship wreck visible through clear water.

Legend has it fairies gathered at the site of this medieval castle.

The complex has been abandoned since the Croatian War of Independence, barring a stint as a set for 'Game of Thrones.'

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

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

This stunning, out-of-the-way Croatian monument commemorates a community's uprising against occupying fascist forces.

Yugoslavia's biggest underground airport lies in ruins.

A wonderfully strange collection of 500+ stuffed frogs doing people things.

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.

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

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