The digital collection British First World War Trench Maps, 1915-1918 is a project of the National Library of Scotland (NLS), Edinburgh, at their special subdomain for digitized historical maps. Although the NLS alerts to the incompleteness of their collection this digital collection with 21 maps at 1:5,000, 88 maps at 1:10,000, 198 maps at 1:20,000, and 1 map at 1:40,000 scale, is most interesting. The maps come mainly from the series GSGS 2742 (1:20,000) and GSGS 3062 (1:10,000) and document trenches in Belgium, in particular in Flanders, and in France between 1915 and 1918. The website provides background information about the maps which were mainly created by the Ordnance Survey. After choosing the category “Belgium / France, Trench Maps” from a drop down list at the NLS maps search interface (Find a place) you can select a map from the sections indicated on a zoomable map of Belgium and France.