I just finished a book about Sgt Reckless. A horse with quite a history in the Army. He was used to transport artillery shells in Korea. Was wounded several times and got to where he didn't even have to be led, they would load him up and he'd just know where he had to go. Steep difficult terrain, save a lot of work for the Guys.
Guess he has a special resting place in Camp Pendleton, they actually shipped him home from Korea where he was born and he lived a full life on the base, sired a couple colts too.