What if one of the most pivotal events of the 20th century was, in fact, a cover up? That's the question at the heart of "JFK: Revisited", Oliver Stone's new documentary about the political assassination that shook America to its core in 1963. Thirty years after his drama "JFK" starring Kevin Costner was released, the filmmaker joins us to talk about the conspiracy theories that - in some cases - reveal themselves to be conspiracy fact.