During the Battle of the Somme 1916
Imperial War Museum Catalog # Q3990
The Battle of the Somme in 1916 turned into a meat grinder. By the end of the long battle, some 400,000 British Empire soldiers would be casualties. Total casualties from all sides would reach 1,000,000 in this battle.
This removed in time, 94 years later, one has to ask if there is any interest left. The answer as the Independent in the UK discovered last year is an emphatic yes with almost 2,000,000 visits. A barn in the Somme region was renovated in 2007 and hundreds of glass plate negatives were tossed out onto the rubbish pile. Luckily 400 of these plates were found, digitised, and restored by two men, Barnard Gardin and Dominique Zanardi, showing unknown Empire soldiers just before the Battle of the Somme started. A slideshow of 286 pictures can be found here. Of all the people shown in these recovered pictures, only one has been positively identified.