On the topic of genocide, there's good news and bad news. There is a documentary film out which aims to shed light on the subject so that genocide becomes less likely in the future.
While this is a noble goal, unfortunately the filmmakers' own biases distort history by omission of many important facts.
While many instances of genocide are discussed in the film, such as the holocaust, Rwanda, Armenia, and others, the two greatest genocides, those in Stalinist Russia and the Chinese genocide under Mao, aren't even worth a mention.
More important still is the omission of information about how almost every major genocide in history was preceded by confiscation of arms that the people could have used to defend themselves. To add insult to injury, it appears as though the filmmakers, to further their agenda, are using this film as a propaganda tool to push for stringent worldwide gun control laws.
Check out this important article in which the author reviews the film and discusses his confrontation with the filmmakers regarding their significant omissions.
Omission of facts by accident is a mistake. Omission of facts on purpose is lying.