The stabilised front line (1915)
The front line was stabilised by late 1915 and would scarcely move until 1918. It was made up of a dense network of trenches. On both the German and French sides, these complex defensive systems could be up to 500m thick. Front line, intermediary and support trenches ran parallel to one another, connected by numerous communication tunnels to form a gigantic cobweb which is still visible over dozens of hectares of the forest floor. This sprawling, practically impregnable first line of defence was nonetheless backed up by further defensive lines. On the French side, one mile south of the front on the other slope of the Biesme valley across from the French camps, stand the ruins of the second line of defence.