Over the course of 72 hours, Hurricane Katrina went from a cataclysmic storm to a catastrophic flood, which in turn became an apocalyptic human tragedy. All the while, amateur videographers, news crews, and countless others were recording the sights and sounds of the unfolding chaos. Weaving together more than a dozen of these sources, Witness: Katrina reconstructs Hurricane Katrina as it happened, entirely through the eyes of those who experienced it.