The Hindenburg Line
The German army retreats to a stronger line of defences called the Hindenburg Line.
In February 1917 the German soldiers in the Somme area began retreating. It wasn't a disorganised retreat. It was a carefully planned, secret retreat carried out on purpose.
The Germans had started building a new, very strong line of defences in 1916. By 1917 they were having to fight in lots of different places and their army had suffered huge numbers of casualties in battles such as Verdun and the Somme. They needed to make the best use of the soldiers they had left available on the Western Front. The strong new line could be defended with fewer soldiers and behind this protective barrier Germany could work out new ways of defeating the Allies. The Germans called it the Siegfried Line but the Allies knew it as the Hindenburg Line. It was built with the assistance of forced labour by civilians and Russian prisoners of war and was made up of a series of fortified trench systems and strongpoints, heavily defended by machine guns.
A map showing the start and end point of the German withdrawal.
An army needs constant supplies. In this film weapons and other supplies are being transported on carts pulled by horses. However armies could also use railways to move supplies longer distances. Motor vehicles were also available but they could be unreliable.