“If you always do as you’re told, then you don’t ever change anything,” an alumna of the Greenham Common Women’s Peace Camp observes in the new trailer for “Mothers of the Revolution.” Directed by Briar March and narrated by Glenda Jackson, the documentary tells the story of “the ordinary women who helped end the Cold War.”

In 1981, a group of women who were fed up with the arms race and the constant threat of nuclear war marched 120 miles from Cardiff to Berkshire to protest the housing of American missiles on U.K. soil. Over 70,000 women eventually join their cause, resulting in the Greenham Common Women’s Peace Camp. The movement “challenged world leaders, altering the course of history, and went on to inspire millions as the world’s first and biggest female-only demonstration, preceded only by the suffragettes,” as a press release details.

Featuring interviews with participants such as Julie Christie and Rebecca Johnson, archival footage, and re-enactments, “Mothers of the Revolution” traces the obstacles the Greenham women encountered and the strides they made. Even when they were threatened or physically endangered, the knew they had to stay committed to the movement.

“Whatever campaign we had, we’d started it and it had to continue,” an interviewee explains in the spot. “The risks of doing nothing were greater than the risks of doing something,” another adds.

March previously helmed docs “There Once was an Island: Te Henua e Nnoho” and “A Place to Call Home.” Jackson can be seen next in romantic drama “Mothering Sunday,” which will begin screening at TIFF next week.

“Mothers of the Revolution” will be available on VOD October 19.