Desc: O Olho do Canhão: Directed by Pedro Rosa. With Nireu Cavalcanti, Roberto Conduru, Villas Boas Corrêa, Sérgio Corrêa da Costa. The Cannon's Eye is a history documentary which tells the story of Rio de Janeiro's fortresses, from the city's foundation in 1565 'til 2004, through the eyes of historians, military officers, architects and writers.