Reds (1981) on Netflix

This movie tells the true story of John Reed, a radical American journalist around the time of World War I. He soon meets Louise Bryant, a respectable married woman, who dumps her husband for Reed and becomes an important feminist and radical in her own right. After involvement with labor and political disputes in the US, they go to Russia in time for the October Revolution in 1917, when the Communists siezed power. Inspired, they return to the US, hoping to lead a similar revolution. A particularly fascinating aspect of the movie is the inclusion of interviews with "witnesses", the real-life surviving participants in the events of the movie.