'Fairy circles' have long been one of nature's greatest mysteries, prompting wild theories they were created by aliens or legendary gods.
These images show the vast areas that are covered by the mysterious fairy circles that pock the grassy desert of Namibia and why they have captivated the imaginations of visitors to the region. But now a team of scientists believe they have finally unravelled what causes these strange circles of bare earth to form in their millions.
Writing in the journal Nature, scientists say these self-organised regular vegetation patterns are created by a combination of plant and insect behaviour.
The researchers from Princeton University and the University of Strathclyde looked at two leading theories for the fairy circles to make the discovery.
The first theory suggests that plants around the fairy circles help their neighbours but compete with distant individuals in a tug-of-war for water and other scarce nutrients.
The tug of war causes the landscape to organise into rings of deep-rooted plants that are capable of draining water from a main reservoir.
The second theory argues the circles are formed by subterranean ecosystem engineers, such as termites, ants or rodents. According to the termite theory, a species called Psammotermes allocerus is engineering the circles by destroying the plants above them.
The two theories on their own aren't enough to explain the bare patches.
But Corina Tarnita and colleagues at Princeton University combined both of these theories into a computer simulation.
They show that, instead of one or the other, a combination of competition between subterranean social-insect colonies of the same species and a tug of war between plants can explain the self-organized regular vegetation patterns.
They believe termites may create the large-scale pattern, and plants help establish a small-scale pattern of fairy circles.
The unusual patterns seen between circles are plants that establish an orderly root system so they don't compete too much for limited water.
"Out of all these processes, where each is doing what they need to, emerges this large scale pattern," Tarnita said. The circular shape is a result of termites venturing as far as possible from their own colony's nest without encroaching on a competing colony.
It's not quite a conspiracy, says co-author Robert Pringle, because the creatures aren't trying to make the patterns. "There's no master plan, there's no kind of blueprint for what's supposed to emerge," he said.
Several outside experts contacted by the Associated Press weren't convinced by the study, because they weren't comfortable with the author's assumptions about rainfall and especially termite colony lifespans.
Last year, photographer Thomas Dressler revealed a series of photographs captured from the air that reveal the scale of these bizarre patches.
Found in hotspots along a 1,242 mile (2,000km) long stretch of desert between Angola and South Africa, they transform the landscape into something more like the surface of the moon.
Mr Dressler, 58, from Marbella, Spain, took the pictures from a hot air balloon and a small plane during three visits to the area between 2010 and 2014. He said: 'I regularly travel to this location because the Namib Desert, including the pre-Namib, for me, belong to the most stunning landscapes on earth. 'I came across this phenomenon by chance during one of my very first visits. 'It was very exciting to fly over the area for the first time.'
The fairy rings, which measure between 6 feet and 40 feet across (2-12 metres), are essentially bare patches of earth in the stubby grass that grows across the Namib desert.
Local legends say the fairy circles are the footsteps of the gods while others have suggested they are burn marks from dragons living beneath the ground.
Some have suggested they may be the landing spots of UFOs or the sleeping spots of Namibia's national animal the oryx. There are some scientists who have suggested the circles are created by radioactive patches of soil that prevent the grass that covers the landscape from growing.
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