The Musketeers of Pig Alley

Martin Scorsese cited this early Griffith short as being the first gangster film. It's very much a "street film" set among the urban poor and focusing on a young couple and the neighborhood hoodlums or "musketeers." The climactic sequence is justly famous -- particularly a scene in which two rival gangs are stalking each other through an alley as one gangster walks up to the camera in what some describe as the invention of the close up (though I'm not sure that's actually true). It is a great shot though.