These are the remains of a "desert kite", a giant animal corral built out of stones some 5,500 years ago. They were effectively the world's first slaughterhouses, as dozens of animals at a time were herded inside and killed.
Desert kites are just one of a number of archaeological sites that modern people only noticed when they flew high above them, realizing there were giant geometric structures on the ground below.
Researchers have since been able to tie these desert kites in with various historical accounts and artistic representations that reveal their animal-centric purpose. However, it appears that they weren't used to protect animals, as earlier theories held, but rather to kill them as efficiently as possible.
We can actually deduce a lot about these kites and the people who made them. The corrals all lie along migration routes that ran from Syria to Saudi Arabia, suggesting the people who built them were well-versed in animal behavior. At the same time, these were no longer the skilled hunters of earlier, nomadic generations.
Instead, these were built long after the Middle East had begun practicing agriculture, and game animals were so common anyway that, in all likelihood, these kites were just a leisure activity for the idle rich. This may partially explain why their preferred game, such as wild asses and gazelles, are now all but gone in places like northeastern Syria, where a lot of these kites were found.
The sheer scale of these ancient slaughters is hard to imagine. There's strong evidence that as many as 93 gazelles were killed in a single session, and even more incredible is an archaeological layer in the ancient town of Tell Kuran, where over 2,600 Persian gazelle bones were found clumped together. Most of those bones were feet, suggesting that several hundred gazelles may have been killed over a very short period.
Via PNAS. Photo by Yann Arthus-Bertrand.