Coppola shot an unprecedented 1.5 million feet of film for Apocalypse Now (1979). This massive amount of footage took years to edit, leading to the creation of several different versions of the film, including the Redux and the Final Cut.
So Robert Duvall died. Terrible news - he was an outstanding actor, great range - made every film/show he did better.
I always liked this scene from Apocalypse Now where he forces his soldiers to go surfing in the middle of a combat zone because the waves were just too good.