The last time all known U.S. veterans of a war died was Sept. 10, 1992, when Spanish-American War veteran Nathan E. Cook passed away at age 106.
As a kid back in the 1950s, I knew a lot of old (grandfather types) who were WWI Vets. But there was one old guy who was the neighborhood Chiropractor and an avid stamp collector. His name was Doc Winston. He was a very nice man. He got me interested in stamps then, sadly it didn't last for long. ( I was more into baseball cards then. ;~))
The guy was in his 80s I'd guess and still practicing. One time talking to him, he told me he was a veteran of not only the Spanish-American war, but also marched into Peking during the Boxer Rebellion.
I wish I had been old enough or smart enough to either record or write down his recollections of that time. I loved talking to him, but I just can't remember much of about the stories he told. I just knew I really liked that old guy and his history fascinated me then.
But tell your kids that when they meet an old timer who wants to tell them about 'the day' to find a way to preserve those memories.
My great grandfather was born in 1899. He never fought in any war. His older brothers went off to WWI. I always assumed my great grandfather was too young to go to war in WWI. But apparently not.