57c.E2 [Canal du Nord, Lock no.4] September 4, 1918
Oblique angle photo. Covers an area equivalent to squares E2, 8 and 9 on the corresponding WWI map sheet 57c. Negative roll 13LB, photo number 3510. Annotations on recto: north arrow pointing to bottom. "Lock no.4." and map reference "E.2.a.80.05" pointing to a collapsed bridge labelled in white. The letter "K" printed in green ink. WWI Aerial Photograph Collection: Box 4, Album photo 19.