Okay, maybe that headline is a little misleading; we have a pretty good idea these giant bizarre installations of concrete and steel were built by human architects, but that's pretty much the only down-to-earth thing we can say about them.
"Spomenik #1" Photo by Jan Kempenaers
These threatening structures are actually World War II memorials, commissioned by the hundreds in the '60s and '70s by Josip Tito, the dictator who ruled the former Yugoslavia until his death in 1980. The reason they don't actually depict war heroes – or any other human figures, for that matter – is because Tito's strict political philosophy forbid honoring any specific person or group.
"Spomenik #16" Photo by Jan Kempenaers
Many of the monuments were destroyed after the fall of the Soviet Union, but those still standing have been documented by Jan Kempenaers, a Belgian photographer and chronicler of “geographical oddities” as part of a book entitled Spomenik (the Serbo-Croatian word for monument). He wanted to preserve them for posterity – even though the locals didn't seem to care about the alien shapes.
"Spomenik #11" Photo by Jan Kempenaers
"Someone in a Croatian magazine wrote that this crazy European guy is coming to take pictures of our relics of a forgotten past,” Kempenaers told The Guardian during a London showing of his work, “and that I was really, really weird.”
The Guardian is also hosting a slideshow of Kempenaers's Spomenik subjects here.