File:Two German shells bursting in our lines.jpg

English: Two shells exploding in the distance. According to the existing caption they have been fired by the Germans and are exploding on Allied lines. They appear as two large puffs of smoke in the sky. It is impossible from this distance to see the damage they have caused. In the foreground there is a trench, with sandbags visible on one side, and a wooden cross, probably marking a grave. The ground stretching into the distance is muddy and churned up.

Soldiers under constant shell-fire had a very good chance of developing shell-shock. Beginning with minor symptoms such as tiredness and headaches, it could eventually lead to a complete mental breakdown. Despite being a recognised medical condition, it went unrecognised by the Military for many years.