Luis Buñuel’s discovery of feral youth, made in the slums of Mexico City in 1950. Buñuel’s apparent lack of compassion for his juvenile delinquents is what finally makes the film an unusually powerful social document and a disturbing piece of drama. He explains them with neither sympathy nor sentiment, but simply produces the brutal facts of their lives. Gabriel Figueroa, the great Mexican cameraman, contributes a harsh black-and-white image that transcends documentary—it’s real life, only more so. In Spanish with subtitles.