Shoah (1985)

Claude Lanzmann directed this 9 1/2 hour documentary of the Holocaust without using a single frame of archive footage. He interviews survivors, witnesses, and ex-Nazis (whom he had to film secretly since though only agreed to be interviewed by audio). His style of interviewing by asking for the most minute details is effective at adding up these details to give a horrifying portrait of the events of Nazi genocide. He also shows, or rather lets some of his subjects themselves show, that the anti-Semitism that caused 6 million Jews to die in the Holocaust is still alive in well in many people that still live in Germany, Poland, and elsewhere.