"You'd be surprised what the human mind and body can adjust to," says Tito, one of the tunnel dwellers. He and his neighbors are homeless, but the tunnels offer them a degree of safety that doesn't exist on the streets above. In this strange place they manage to achieve a remarkable degree of domesticity, building shelters, keeping pets, and cooking meals.

Singer has an eye for telling images, such as Dee dragging a sofa along the train tracks like Sisyphus rolling his stone in Hell. With its grainy black-and-white photography and haunting soundtrack, this is a surprisingly beautiful film, but it is never sentimental, nor does it try to impose a false nobility on its subjects. Dark Days simply shows us a world that we never knew existed, and in this simplicity lies its power. --Simon Leake