On October 21, 1967, 100,000 protesters march through West Potomac Park in Washington DC in the well-organized “Mobilization to End the War in Vietnam” protest. Subsequently 35,000 of these protestors take direct action by marching on the Pentagon to be met by armed soldiers and riot police.

The Sixth Side of the Pentagon is a sympathetic account of the historic march on the Pentagon, featuring dramatic eyewitness footage of an event that marked a turning point in the American attitude towards the Vietnam War. Filming within the crowd, Marker and Reichenbach get dangerously close to the action, as the protesters rush the barricades around the Pentagon building before being pushed back by nervous young recruits. Even after nearly fifty years you can feel the raw emotions of those present and shots of a bloodied but defiant young student facing up to a truncheon-wielding policeman still seem shocking.

In contrast to the violent visuals, Marker’s dry narration provides a factual and sometimes wry commentary on events as they unfold (of protestors attempting to exorcise evil from the Pentagon, he comments: “They had asked permission from the authorities to have the Pentagon levitated up to three hundred yards above the ground. They received permission for only ten yards”). There is no pretence at objectivity, Marker is full square behind the protestors and the film could be fairly described as a work of agitprop. Over the opening black and white image of the fortress-like Pentagon complex, he describes the building as a “city within the city, state within the state, whichever, it stands for the American war and at this stage for the war in Vietnam". This is followed by shots in the small, busy offices of the protest movement, which are reassuring human in comparison to the monolithic Pentagon. Marker lauds those protestors who, having taken direct action, have “crossed a threshold, from political gestures they have moved on to political action”.

The documentary concludes with a black and white montage of stills and live action, including Marc Riboud’s famous photograph of a young woman holding a flower in front of police lines, students burning their draft cards, and images of those incarcerated overnight in police cells who include Norman Mailer and Shirley Clarke. Their mood is one of optimism: change is possible. In fact the Vietnam War would drag on for another eight years despite escalating resistance. In documenting the major opening salvo in the public opposition to the war, The Sixth Side of the Pentagon, like Mailer’s nonfiction novel The Armies of the Night, remains an important witness statement from history.