Shot in the liberated zones of Guinea-Bissau during its war against Portuguese occupation, Sarah Maldoror's Algerian-funded feature about a woman in the armed struggle was never completed for release after Algerian authorities, objecting to its female lead and jazz score, gave Maldoror 48 hours to leave the country and confiscated the footage, which remains lost.
Fun fact: A 2011 documentary short by Mathieu Kleyebe Abonnenc, Foreword to Guns for Banta, investigates the film's disappearance and its status as one of African cinema's great lost works.