When the initial battles of 1914 had ground to a halt after the Allies and German Armies tried to outflank each other until they had reached the North Sea in Belgium, there was nothing to do but dig trenches to stay safe from the bullets and grenades.
Trenches were dug on both sides and the armies largely remained there until the end of the war. Occasionally some ground was gained here and there, but this was always with many men killed, wounded or missing.
Throughout the war the trenches were improved upon. They were dug deeper and were better fortified. Drainage systems were developed, and deep shelters were dug to protect the men from bombardements, to provide living quarters for officers and for first aid posts.
The German and English trenches were well build, using wooden planks, concrete, sandbags, rocks etc. The Germans especially had good strong trenches, sometimes made out of concrete. This was because they were not planning on going anywhere. They were there to occupy and capture France so they had time to fortify their trenches. The French on the other hand wanted to drive the Germans out of their country. They were on the offensive and did not intend to stay in one place for very long. As a result their trenches were not so well build. That is why today many German trenches can still be found, whereas the French trenches have often disappeared with time. And, ofcourse, it also depended on what type of soil the trenches were dug in.
A good example of the diffence in trenches can be seen in the Bois de Brûle near St-Mihiel. The original German trenches are still there, some build out of stone, with firesteps and loopholes through which you can see the French side across no mans land. The French trenches are all but gone, but a small part has been rebuild, giving us an excellent view of the differences of trench building on both sides.
In the western part of France and in Belgium most of the trenches have disappeared. As these regions mainly consist of farmland, the farmers reclaimed their land after the war and filled in the trenches so they could start farming again. Only a few places have remained where the original trenches can be seen, such as at the Bayern Wald site in Belgium and at the Newfoundland Memorial Park at Gueudecourt on the Somme.
When ground is being prepared for building projects on the former battlefields, many relics and sometimes bodies are found, and archeologists and other specialists are called in to excavate these sites. Traces of the filled in trenches are found and excavated. Deep undergound shelters are also often found. Along the canal in Boezinge near Ypres, on what is now an Industrial site, local enthousiasts (a group who called themselves ‘the diggers’) together with the “In Flanders Fields museum”, have been able to preserve a part of a trench and made the site available for tourists to visit. This trench, known as the ‘Yorkshire Trench’, has for a small part been excavated and preserved, with the entrance and exit to a deep dug-out visible (although it is filled with water). On the rest of the site where trenches used to be, a path has been laid on the ground to show how the trench sytem used to run. In this way they have preserved another relic of the war for future generations to visit and learn about trench warfare.