Seabiscuit
Credit: Getty Images

Why he hung it up: The American Horse of the Year in 1938 ruptured a ligament in his leg and trainers thought his glorious career was over.

Why he returned: Ever-resilient, Seabiscuit recovered in time to race during the 1940 season.

Success: Seabiscuit proved ever the comeback kid, winning the Santa Ana Handicap, then retired to stud more than 100 foals.