Roman-era military camps found in Saudi Arabian desertResearchers believe Romans travelled by camel between the camps. A camel shepherd is seen in the desert at sunset in Raqqa city, Syria July 28, 2017. (photo credit: REUTERS/RODI SAID)
A camel shepherd is seen in the desert at sunset in Raqqa city, Syria July 28, 2017. (photo credit: REUTERS/RODI SAID)