In the winter of 1914-15 all the soldiers on the Western Front believed that the trenches were only temporary structures. They thought that as soon as the good spring weather arrived, the armies would return to traditional fighting tactics.
The trenches were based on temporary field defences that all armies built when stationary for a few days. They were designed to shelter men from artillery shells and rifle bullets.
Trenches were designed to be over 2.3 metres deep, so that men could walk along them without needing to crouch. Often trenches were much shallower than this.
A firing step was built into the front of the trench. Standing on this step a man could aim his rifle over the top of the trench towards the enemy. Sentries stood on the firing step to see if the enemy were attacking.
Trenches were built in zig-zag routes so that there was no straight stretch of more than 30 metres. This was so that nobody could aim a gun along the trench to kill everyone in it.
In 1914 there were usually two or three lines of trenches. The front trench contained most of the men, ready to repel an enemy attack. The second and third trenches contained first aid posts, kitchens, latrines and other essential services.
The different lines of trenches were linked by communication trenches that ran forwards. These were not as deep as the line trenches and did not have firing steps.
In marshy areas or rainy weather, the trenches often filled with water very quickly. Hand-powered pumps were installed to keep the trenches dry, but they did not work very effectively.
Sandbags and wooden planks were widely used to give strength and shape to the trench walls. Collapsing trenches were a problem throughout the winter in all areas.
Barbed wire was strung on a line of metal posts in front of the trenches. This would slow down any attacking soldiers so that the defenders had more time to shoot them.
This is an extract from 1000 Facts on World War I by Rupert Matthews