YANKS TOURING LONDON ON THE FOURTH. 
The four-in-hand coach was one of many vehicles furnished by the English, are a part of their celebration of Independence Day, 1918 to enable the American soldiers and sailors to see London City and the metropolis.
Air Service, United States Army photograph
1918
National Archives of the United States via Gorrell's History of the American Expeditionary Forces Air Service, 1917-1919, Series B, Air Service Activities with the French, British, and Italians, Volume 2, History of the Air Service in Great Britain