In the 1920s, pilots flying low over the desert on the mail run between Cairo and Baghdad noticed 'mysterious walls'. The structures, which resembled giant keyholes, were easier to spot from the air than from the ground. At the time, they were thought to be ancient fortifications.

In the 1950s, when similar structures were spotted in central Asia on the Ustyurt Plateau between the Aral Sea and the Caspian Sea, Soviet newspapers suggested that the formations had been built by extraterrestrials. Now archaeologists from the University of Sydney and the University of Nukus in Uzbekistan have a more down-to-earth explanation. They are convinced that the structures were built thousands of years ago by nomadic tribes to trap herds of animals, especially gazelle, antelope and oryx.
The scale of the killing was great. According to Alison Betts of the University of Sydney, far more animals died than the nomadic peoples could possibly have needed for food and clothing. The carcasses must therefore have been used for other purposes. Betts and her colleagues believe that the animals snared in central Asia could have been used for trade along the Silk Route between China and Europe.

24 September 1994
New Scientist