From left to right:
The Turco area on 24 June 1915 (British map).
The Turco area on 5 May 1916 (French map, Région de Merckem-Ypres, 1:20,000).
The Turco area on 9 September 1916 (British map).
The Turco area in December 1916 (British map, 1:10,000).


From left to right:
The Turco area on 30 June1917 (British map, St Julien, 1:10,000).
The Turco area on 22 July 1917 (British map).
The Turco area on 30 March 1918 (British classified map, St. Julien, 1:10,000).

It appears that aerial photographs offer us a much more reliable image than the trench maps. The aerial photographs show us a clear evolution in the appearance of the trenches, while the same trench is sometimes depicted in a totally different manner on different trenchmaps.