Greed

Greed is a 1924 silent film directed by Erich von Stroheim (Foolish Wives, Grand Illusion, Sunset Boulevard, Great Gabbo). It has been restored by using still photographs in place of lost film footage. It is based on the Frank Norris novel McTeague, which can be read online here.

The 4-hour version of Greed can be seen at youtube divided into 29 parts. Part 1:

part 2, part 3, part 4, part 5, part 6, part 7, part 8, part 9, part 10, part 11, part 12, part 13, part 14, part 15, part 16, part 17, part 18, part 19, part 20, part 21, part 22, part 23, part 24, part 25, part 26, part 27, part 28, part 29

Or watch it in one go at this link.

The Guardian says

Part of the story's greatness, in both the novel and Stroheim's adaptation, is the degree to which it makes the deterioration of all three characters terrifyingly believable.

Roger Ebert considers it one of the "great movies" and begins his review by saying that the film:

is acclaimed as a classic despite missing several parts deemed essential by its creator. Its unhappy history is well known. Von Stroheim's original film was more than nine hours long. After it was cut, cut and cut again, it was released at about 140 minutes, in a version that he disowned--and that inspired a fistfight with Louis B. Mayer. It is this version that is often voted one of the greatest films of all time.

The New York Times has a review. FilmReference.com has a list of resources and an article about the film. Film Monthly also has an article.