Dunkirk Trailer Breakdown: 21 Things You Need To See

9. Human Carnage

Well, that's a horrifying image. Murphy helps Rylance's son rescue two men out of the water, who appear to be soaked in crude oil.

Perhaps the soldiers were caught in the engine room in the middle of an enemy attack, and as such got doused in the black stuff, or maybe it leaked out into the sea as they were swimming away from the wreckage.