A-frame sinking into the mud and first aid dog surveying the trench.
Slope entrance doorways to allow a gas blanket to form a firm seal by gravity.
After third Ypres individual post with elephant shelters were used by the British instead of continuous front trench lines.
Below a 66th division instructive drawing.
Section of dugout frame within a trench parapet, with front and rear ‘borrow pits’ – the earth from which was used to build parapet and parados.