Reckless, the mare.
This horse was a packhorse during the Korean war, and she carried recoilless rifles, ammunition and supplies to Marines. Nothing too unusual about that, lots of animals got pressed into doing pack chores in many wars.
But this horse did something more..during the battle for a location called Outpost Vegas, this mare made 50 trips up and down the hill, on the way up she carried ammunition, and on the way down she carried wounded soldiers.
What was so amazing? Well she made every one of those trips without anyone leading her.
Great story, it would make an excellent (non politically correct) Movie.