I have just listened to the free audio book "South" available at Librivox.
WOW!
It is Ernest Shackeltons story of his expedition to the Southern pole.
If you dont know the story, prepare to be blown away by the amazing story of human suffering, human strength, human endurance and of course the personal will and character of the man himself.
If you only listen to one non-fiction audio book, listen to "South".