Series Number Id: UNKNOWN. Sheet number: part of sheet 57. Edition number: 2. At head of map: D.15-L.32. "Trenches corrected from information received up to 10-5-17." "5th Field Survey Co R.E. (980) 11-5-17". Grey detail. Hindenburg Line and other German trenches in red., Location: Research Collections; Fonds: WW1 Trench Maps: France; Box number: PC15; envelope_number: 414.