Wow, this is so interesting.
My Great Uncle George emigrated to Canada before the war and joined up to fight in 1915. He was only in France for about 10 days before he was killed on the 26th September, 1916. There is no known grave, but my Great Grandmother made inquiries in 1923, to try and find it. No luck!.
His name is on the memorial at Vimy Ridge (Canadian), which myself and husband visited a few years back. We also visited the village were he was killed, and the war graves there. He may be one of the unnamed buried there.
It's amazing the connections we still have to this dreadful period in our history.