Every time we record an event in video or make a movie, it is somewhat like freezing moments that are carried into the future. Thus, watching old documentaries is somewhat like time travel. You may alter the film as is often done at the time of making, creating two or more stories, but that does not change the future except how it impacts those watching it. For instance. I recently saw a documentary on Indonesia under the brutal dictatorship of Suharto who put a third of his population to genocide in 1965-66. This story was under reported at the time if reported at all. When I finally became aware of this hidden genocide, it had a profound effect on me, causing me to wonder what else has been hidden from sight. A movie was also made about this bloody atrocity. called "The Year of Living Dangerously". I saw the movie, but did not make the connection to the real event until I "time traveled" to the era and location via documentary accounts. It did have a profound effect on me! The past can affect the present and future!