Absolutely incredible. The first hand survivor accounts take you from utter fear and hopelessness to tears of joy. It breaks your heart and then puts it back together. It's hard to watch, and to relive that horrifying day (definitely have an econo sized box of kleenex on hand), but this truly is one of the best documentaries I've ever seen. I also appreciate that it never mentions politics or conspiracy theories or any of that fodder. It's just first hand survivor accounts and video footage of that days events, which is what makes it so impactful.