A few years ago I and an ex of mine went to see the WW1 battle fields in Belgium. These are some of the photos.
The ex and her great-grandparents. They both died just before the war and it took until 1924 before the ground was cleared and he (her grandfather) could get to the village to erect the crosses over his parents.
Usually, after the war the grave pits were exhumed and the bodies interred in cemeteries. You know the places that were undisturbed by the nearness of the stones. These two photos are of Lijsenthoek cemetery outside Ypres in Flanders. It holds just 10,000, mostly 20 year old’s.