I have to admit I was totally unaware of this until I sat down with two survivors of this march in 2005. How they kept their sanity I'll never know. https://ww2thebigone.com/2016/04/22/the-long-awful-march-from-stalag-luft-iv/
hell .that's what it was....moving one foot in front of the other....time after time, etc etc ....numbness of body and brain to where that gets to be 'normal'