This feat of Brutalist architecture is also known as the Three Sisters.

Two buildings named after their windows that make it look like a sea of television sets plastered to a wall.

One of Serbia's oldest luxury hotels and a nostalgic echo to Yugoslavia in the state's former capital.

Memorial to the victims of the Holocaust in Serbia.

A neglected spomenik overlooking the beautiful Kopaonik Mountains.

This memorial park stands on the site of one of the largest mass executions of the Second World War.

A Serbian monument to plums.

A supersonic jet stands on a pedestal in this rural village as a monument to military aviation.

This demolished goliath of American industry once loomed over the depressed town it once made thrive.

A train station that was abandoned by the coal industry and was later converted into a cocktail bar.

The vast chamber inside this abandoned cooling tower looks like something out of a sci-fi dystopia.

A crumbling island fortress that seems to be covered in a field of stone crosses but is simply incomplete.

It's believed that the dead were once taken out of houses through these now walled-up doors.

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

The music is over at the Ballhaus Riviera Ballroom, but the ballroom remains in haunting disrepair.

Once swallowed by flood waters, this village has emerged as an eerie shadow of its former self.

A dormant lightning machine equal to all the power in Russia.

A former seaside jewel built for the everyman is now simply a neglected art deco fortress.

When Croatia became independent of Yugoslavia, the splintering governments left behind these concrete tunnels.

These disused steel furnaces are now haunting ruins that may one day be a national park.

This real life asylum of horrors is now an abandoned ruin that hides the unbreakable code to one patient's insanity.

This crumbling UFO is one of only a few remaining "moveable ski chalets" of its kind.

Decades after testing the polio vaccine on unwitting patients, this historic mental hospital sits in ruin.

The "Fun Spot of the Desert" is now a haunting ruin, and a reminder that putting a water park in a desert is a bad idea.