If you look really closely (like one of those paintings you stare at and the image finally pops out) at the opening scene of Apocalypse, there is the face of a man screaming superimposed over the trees. It is most easily scene when the smoke muffles the image. The image is just to the left of the middle of the screen. It is very subtle. I believe coppola superimposed an image of a man screaming over the trees.