The climactic scenes of the 1981 movie 'Gallipoli', one of the best WW1 movies ever made in my opinion.
The tragedy of Mel Gibson's character not making it back to the lines in time to stop his comrades going "over the top" into the slaughter and the iconic image of the young soldier being shot and the frame freezing, mirroring earlier images of him crossing the winning line in races back home in Australia, sum up the absolute waste of life in WW1 better than most movies ever have done.
