The photograph above, taken by W. Robert Moore, appeared in the National Geographic Magazine December, 1938 issue (p. 732). The caption reads:

THE DESERT-GOING BAGHDAD-DAMASCUS BUS IS AIR-COOLED AND WAS “MADE IN U.S.A.”
Temperature was 111 degrees Fahrenheit when the picture ws taken at Baghdad’s airport, but inside the stainless-steel bus, operated by Nairn Transport Company, it was only 76 degrees. Now, in a few hours, these huge high-speed cars make the trip that once took camels many days.