The documentary was produced using footage of the rally originally intended for newsreels that had never been widely issued due to its controversial content. Many film exhibitors avoided footage of Hitler and Nazism due to strongly negative reactions and even disorderly conduct from audiences. "News of the Day" never released its footage, while RKO-Pathé News quickly withdrew a newsreel incorporating the footage after deeming it "too inflammatory." As a result, the rally was widely forgotten after the end of World War II. After viewing the footage and expressing surprise at the event's obscurity, Curry was inspired to produce the documentary by the rise of the alt-right in the United States and the 2017 Unite the Right rally in Charlottesville, Virginia. The footage was retrieved and edited from the National Archives, the Grinberg Film Library, Streamline Films, and the UCLA Film and Television Archive.