20.U6 [Owl's Wood and Colombo House, Houthulst Forest] December 18, 1917
Covers an area equivalent to squares O35, 36, U5, and 6 on the corresponding WWI map sheet 20. Negative roll 9B, photo186. Annotations on recto: north arrow pointing to upper-left. WWI Aerial Photograph Collection: Box 1, Envelope 45.