A real masterpiece. Hour of the Furnaces got some play on the Festival circuit in 1968/9, but was largely condescended as a "third world issues" movie, which is doubly insulting, as it was the product of a revolutionary film and political theory based on battling the hegemony of Western auteurist cinema and Soviet social-realism. Argentinian directors Fernando Solanas and Octavio Getino laid out their argument in "Toward a Third Cinema", an essay well worth reading for anyone interested in anti-imperialism, revolutionary politics and cinema. But it pales in comparison to the film they made together.
Watch it. Hour of the Furnaces was made illegally from 1966-1968, and was screened in clandestine gatherings of workers and revolutionaries, who frequently interrupted the film to discuss the points being made. Screenings usually became fervent meetings and on at least one occasion led to a spontaneous riot. Watch it now, and you'll know why.