This is a simply outstanding two-part program from the BBC back in 2004. They interviewed the last surviving British veterans of the War To End War. I cannot recommend this too highly.
The eleventh hour of the eleventh day of the eleventh month is a sacred moment. Hearing the stories from the men themselves will help you reach across the age that separates us from the trenches. I wonder what Grandpa would have thought of this. He served in that war, but as an American, he was late to the party.