Click here to see a video about the atrocity that was Communism, from its Marxist/Darwinian theoretical beginnings through Castro (the intro implies the video will discuss Castro). I've just started watching it, and it looks pretty good. There's neat (though often violent) footage and good commentary. From the video's web page:
Communism was the bloodiest ideology that caused more than 120 million innocent deaths in the 20th century. It was a nightmare which promised equality and justice, but which brought only bloodshed, death, torture and fear. This three-volume documentary displays the terrible savagery of communism and its underlying philosophy. From Marx to Lenin, Stalin, Mao or Pol Pot, discover how the materialist philosophy transforms humans into theorists of violence and masters of cruelty.