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

Gargoyle head that brings good luck.

The now-overgrown beach resort was once frequented by Yugoslav military elite.

The oldest arboretum on the Dalmatian coast doubles as the gardens of Kings Landing in "Game of Thrones."

A giant sculpture of the legendary "Salmon of Knowledge" celebrates the return of fish to Belfast's River Lagan.

This platform is now a memorial dedicated to those who were deported during the Holocaust.

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

This unique structure allowed boats to bypass underwater mine barriers in the channel to enter the harbor.

This 1960's Soviet submarine in Peenemünde Harbor claims to be the largest submarine museum in the world.

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

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

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

A collection of old neon signs from all over Poland line a secluded courtyard.

This centuries-old wooden wonder was built in less than a year and is one of Europe's largest timber-framed churches.

A mysterious structure left behind on the Polish mountainside, sometimes called "Hitler's Stonehenge".

Created as a "model concentration camp" to hide Nazi atrocities from the international community, this former camp-ghetto now holds a museum and memorial honoring the lives lost within.

An Austrian house of bones filled with hundreds of intricately painted skulls.

This cubist Vienna church building looks like some sort of alien stonehenge.

Ugly 18th-century dwarf statues living in a perfectly landscaped Austrian garden.

Terrifically morbid cemetary and site of famous Paracelsus' grave.

The housing complex served as an anti-fascist fortress during the Austrian Civil War.

Artfully arranged bones of 5,800 Austrians.

Double spiral staircases are not unheard of, but they are very rare.

Resting in the middle of an Austrian river, this sci-fi "island" lets people cross in neon style.