In the deserts of the Middle East are huge ancient stone circles. Their purpose is more mysterious than the superficially similar objects in northern Europe, but archaeologist David Kennedy hopes images taken from the sky will solve the puzzle.

From the ground, the circles don’t have the impressive height of Stonehenge. However, with diameters of up to 400 meters (1,312 feet), they would have required perhaps a hundred worker days to build, as well as some planning.

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