One of the oddest things going on in the background of the film happens in the dirt and in the mud. Occasionally in the background of scenes; and one or two times front and center; you might notice soldiers scooping up dirt with their hands and putting it into small tins, before writing the name of the country on the lid and pocketing them.
Both then and now, this behavior is actually common in soldiers serving abroad. They take a little of the dirt beneath their feet back home with them, as a memento of where they've fought; a little like how you might buy a picture postcard of a place you've visited on vacation. That may seem like an odd hobby, but given the conditions that the soldiers of the time were facing we think it's fine for them to indulge the occasional quirk if it helps them to stay sane.