In “City of God,” dozens of characters appear over three decades in and around a notorious favela, or slum, in Rio de Janeiro, but the neighborhood takes the starring role. It exacts a devastating toll on the lives of its inhabitants, many of whom moved to the Brazilian government project in the 1960s — and then became trapped in the decaying monster’s belly of poverty and violence.

The movie follows Rocket, an aspiring photographer, as he endures 30 years in a neighborhood that, in a sick joke, gained the name the City of God. He watches his childhood pals jockey for influence in the only power structure available, gangs.

Director Fernando Meirelles portrays the futile and cyclical nature of gang warfare in a place without a government, a working economy or much hope for the future. “City of God,” which is based on a true story, unravels through the eyes of Rocket (Alexandre Rodrigues), who remembers his time in the favela with nostalgia after escaping its grasp. His narration covers dozens of characters and events.

There is Lil’ Dice, a smart but violence-obsessed boy who grows up, renames himself Lil’ Ze (Leandro Firmino da Hora), and claws his way to become king of the favela. In contrast is Knockout Ned (Seu Jorge), a straight-arrow transit employee who urges Rocket and his friends to study. But when the gang warfare hits Knockout Ned a little too close to home, he joins up — reluctantly, at first, until the first few kills soften his naivet