RADiUS presents in association with Participant Media ; in co-production with Bertha Foundation, BRITDOC Circle, Channel 4 ; in co-production with Norddeutscher Rundfunk NDR, Bayerischer Rundfunk BR ; with support from Deutscher Filmförderfonds ; producers, Laura Poitras, Mathilde Bonnefoy ; produced by Dirk Wilutzky ; directed by Laura Poitras ; a Praxis Films production in association with Participant Media, HBO Documentary Films