The torturous shooting of of Apocalypse Now has become legendary - scheduled at six weeks but taking nine months (about the same length as principal photography for all three Lord of the Rings movies), running millions of dollars over budget and leading to the mental, emotional and physical collapse of some of its principals, including Martin Sheen and Francis Ford Coppola.
It's a crime that Hearts of Darkness: A Filmmaker's Apocalypse, a documentary using footage and recordings by Coppola's wife Eleanor (some taped secretly), has never been released on DVD, as - totally unlike almost all "making of" pieces - it serves as a true thematic companion piece to the movie itself. The journeys of the characters in the movie mirror the journeys that the cast and crew itself undertake - into a world cut off from the familiar and increasingly grotesque and surreal.
(Trivia: I hadn't realised that River Tam's line "I swallowed a bug" from Serenity was a nod to Kurtz's line in Apocalypse Now. While the reference isn't noted in either movie's imbd entry, given Whedon's parody of the movie in Buffy's "Restless", surely this can't be coincidence.)