Oliver Stone's epic film JFK wasn't really a film about the actual conspiracy theories surrounding the President's assassination. It was a film about obsession. It's about what happens when someone starts getting too deep into a certain subject, and can no longer see anything but. Spotting new things over the same ten seconds of film — that guy waving, the positioning of the Secret Service, the direction the wind was blowing the trees — makes you start filling in blanks that aren't there and forming your own narrative, however sinister that may be.
One of the open canvasses that people have always been able to project onto is the so-called "Umbrella Man" from the Zapruder film. Amidst all of this chaos and commotion (and absolutely zero chance of rain) there stands a lone man with an umbrella. Given a visually-striking image like that, and you can let your mind wonder, turning him into everything from a CIA operative, to a time-traveling visitor from the future, to Castro himself in disguise in Dallas that day to make sure his plan worked.
Leave it to documentary filmmaker Errol Morris, then, to get to the bottom of this mysterious figure. On this, the forty-eighth anniversary of that fateful day, he released a short six-minute doc over at the New York Times website called The Umbrella Man all about this low-profile witness to history. It's pretty great.