The Sahara is the largest hot desert on Earth. 8.6 million square kilometers or 3.3 million square miles of sand dunes and rocks. This is about the size of the U.S., except for the few eastern states - California, Nevada, Oregon, and Washington, buried under the sand. At first sight, this huge kingdom of sand where the surface can heat up to 80° Celsius and the average rainfall is only about 76 millimeters per year isn’t that interesting. And yet, the Sahara is as full of secrets and mysteries a