Man o' War
Greatest racehorse of all time.  Ancestor to War Admiral and Secretariat.  Said to have died of a broken heart after his handler passed away.  Won 21 of his 22 starts.  Once won a race by over 100 lengths.  The one 'loss' was a second and fault of his jockey at the start.

Book by Walter Farley
Man o' War won 21 of his 22 races.  