C. and A.D. 500 by brushing away the dark top layer of barren desert to reveal the light, sandy soil underneath, wrote Clive Ruggles, an archaeologist from the University of Leicester in the United Kingdom, in an email.
One of the Middle East's most scenic and ancient routes, the 280km-long highway is often overlooked in favour of the modern Desert Highway, which marches through Jordan's flat and sandy core in a speedy three and a half hours from the capital, Amman.