Holland's film is extraordinarily generous with its characters in ways that take the story beyond being a historical fable of altruism and endurance.

Though the film's factual basis dictates an upbeat ending, much of the journey is appropriately and memorably grim.

Holland does root around in some grubby, previously unexplored corners, but the film never quite breaks free from that conventional structure.

In Holland’s vision [the sewers] are a filthy and nauseating maze where hope goes to die. When it comes to the escape through stairwells and channels, Holland’s long takes are every bit as sharp and enveloping as Kathryn Bigelow’s point-of-view shots.