Not much is written about religious practices in World War One. What is known comes mostly from soldiers biographies and from postcards.
Of course, in the first half of the 20th century people were much more religious then they are know. But also the ever present danger of being killed or wounded must have made men turn to religion more than before. On sundays, or before the start of a battle, services would be held in or near the camps. On a few places behind the front altars still exist and they are a few of the more interesting and intriguing relics that still remain.
A religious relic that is not so obvious can be found in Talbot House in Poperinge, Belgium behind the former British lines. Talbot House was a club house, opened by chaplains Neville Talbot and Philip “Tubby” Clayton where no distinction in rank or status was made¹. On the attic was the chapel where services were held. An old wooden workbench was used as altar.
After the war Talbot House became a museum and guesthouse and as a result the chapel can still be visited.
¹Source: Talbot House website