Summary: As much as he hates war, the Doctor can't ignore it.
France, in World War I, although the soldiers at that time didn’t know there would be a second global war to follow just a few short decades later. Huddled in their muddy, freezing cold trenches, they believed they were fighting the war to end all wars. Many of them wouldn’t survive to see home again.
The Doctor hated war, there were far better ways of settling differences than by killing each other, but events like these should not be overlooked or ignored; someone needed to bear witness, to remember, to honour those who fell in battle, fighting for their freedom.