Secret military installations or elaborate hoaxes? A series of images captured on Google Maps and showing odd patterns in a Chinese desert have set the tongues of online conspiracy theorists wagging.
The various images - from a white, net-like matrix, to a set of blocks or holes set in a large circle - are located in or near the restive province of Xinjiang in north-west China.
View the other images:
"Perhaps it's some kind of targeting or calibrating grid for Chinese spy satellites? Maybe it's a QR code for aliens? Nobody really knows," technology website Gizmodo speculated.
"It looks like our own Area 51," London's Daily Telegraph newspaper quoted a user on Chinese website Baidu as saying.
Area 51, a US military base in Nevada, has long been touted by conspiracy theorists as a site where research into extra-terrestrials is taking place.
Area 51 ... an alien research site? Photo: Google Maps
But others said the structures, some of which are near Jiuquan, China's space city, could just be training sites for astronauts practising their landings and walks.
They may also be practice ranges for the People's Liberation Army.
"The picture of the circle looks very like a missile test range, with target and instrumentation set out to record weapon effects. The Americans have lots of these in Nevada - Area 51," Tim Ripley of military magazine Jane's Defence Weekly told the Telegraph.
Paul Marks, of the New Scientist magazine, said that, by zooming in on the images, viewers could possibly make out some military planes.
"One of the other formation ... looking tantalisingly like Stonehenge from a great height, zooming in reveals three aircraft sitting at its heart. Clearly, it is some kind of military target for airstrike or gunnery practice," he wrote.
"Another 4 x 4 piece grid some 200 metres across has some pieces clearly blown to smithereens, again supporting the target practice theory, and a dummy runway in garish bluish-white is probably not for style-conscious aliens but air-to-ground strafing practice."
Of course, Google Maps may have been hacked and the images may be part of an elaborate hoax. They could be the "21st century version of crop circles", Marks wrote.
This is not the first time satellite images of China have sparked an online debate.
In 2006, people speculated about what the East Asian giant was building near Huangyangtan, which is about 35 kilometres from Yinchuan in northern China.
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