Picture, if you will, a desert.

Chances are, the picture you now have in your head probably looks a lot like Namib,

Nama'emncloughed National Park in Namibia.

Among the oldest deserts in the world, this park features a spectacular erg, or sand sea, of towering golden-red sand dunes rolling off as far as the eye can see,

one of which, known as Dune 7, is the largest in the world at a whopping 380 meters or 245.25-Ariand-a

grandes tall. Standing amid this desolate, sun-baked landscape, you would expect to be confronted by a profound silence, broken only by the soft whistling of the wind.

But this is no ordinary desert, for every so often the silence

will be shattered by a deep, powerful roaring sound, variously likened to thunder, distant drums,

or the drone of a low sandworm, shy hallood, bless the maker in his water, but is instead produced by the sand itself.

Such singing sands are surprisingly common, appearing in deserts

and on beaches around the world, from Morocco to Kazakhstan, Scotland, Canada, and Hawaii,

and have been the subject of myth and folklore for centuries. Yet despite decades of scientific

investigation, to this day, no one is quite sure what causes these sands to sing. This is the story of one of the last great mysteries of the natural world.

To begin with, singing sands have been known to humanity for thousands of years.

In his influential 1300 travelogue, book of the marvels of the world, Venetian merchant and explorer Marco Polo described invisible desert spirits which, at times, fill the air with the sounds of all kinds of musical instruments, and also of drums and the clash of arms.

Such natural sounds are thought to have inspired the Jin, or Genies of Arabian folklore, and references to singing dunes appear in the 1001 nights and 9th century AD Chinese literature.

Half a century later, British naturalist Charles Darwin also mentioned singing sands in his

1839 Chronicle, Voyage of the Beagle.

Leaving Brazil during the two first days, we retraced our steps.

It was very wearisome work as the road generally ran across a glaring hot sandy plain, not far from the

coast.

I noticed that each time the horse put his foot on the fine siliceous sand, a gentle chirping

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