This is the U.S. Army mail depot at Regents Park, London, braced for and under siege by Christmastime mail in 1917. It strikes me that there are not a million items in this photo--at this time in the war there were something like 35 million people in the services for all countries dedicated to the war effort, which is approximately half the number that served in total. If these letters in this picture were bodies, I reckon that there would be five more rooms like this necessary to tell the visual picture of the war dead and wounded. This aside, I initially focused on the guy in the rear with the white shirt and tie, standing there pretty much overwhelmed by the task of moving all of that stuff...and perhaps with the idea that much of the mound would wind up being undeliverable because the recipient was killed. I wonder if that mail was returned, or not?
On the other end of the spectrum is this bizarrely-titled photo of a British soldier "guiding" a traffic signal device...the description says that this is the busiest intersection in all of British-occupied France. Maybe so, but not at this particular time. Perhaps the photographer should've waited a bit to get a different sort of picture to make his point, rather than settle for this lonely (if not beautifully arranged) situation.
Here's the image without the accompanying text, which was supplied for the end-user of the photo by the news service photography supplier.