UNITED 93, director Paul Greengrass's meticulous reconstruction of the events surrounding the crash--the result of a heroic struggle between the passengers and hijackers--of the fourth plane to be hijacked on September 11, 2001, is a landmark in filmmaking. Greengrass has chosen the most politically and emotionally charged source material available to an artist in the early 21st century, and shaped it into a psychologically draining, terrifyingly real, and technically brilliant film. Like his first feature-length work, BLOODY SUNDAY, UNITED 93 doesn't follow a traditional cinematic narrative structure; via hand-held cameras, grainy DV stock, and frenetic editing, it instead presents a visceral (at times sickening) in-the-moment documentary-style experience that maximizes the film's unavoidable air of tension and dread without being crassly manipulative. Yet for all of its precision and craft, UNITED 93 still depicts one of the most terrifying ordeals the United States has ever had to face--and that it was released less than five years after those events took place plays an undeniably enormous role in how the film is received. It is impossible to watch UNITED 93 and not be profoundly moved, whether that emotion is fear, sadness, anxiety, or pure rage. And it is an emotional catharsis far removed from what is the filmmaker's delicate hand and deft touch. Greengrass, though, is quite fearless in his depiction of the chaos of the day--the President is frustratingly missing; the FAC, NORAD, and local air-traffic control centers are shown in a disoriented panic; and the terrorists are brutal and remorseless--and, to his credit, he avoids soft-pedaling any political agenda and doesn't blindly canonize the flight's passengers. Rather, their heroism is treated as the product of a logical decision made by ordinary men and women who found themselves in the most extraordinary and illogical of situations. And that, ultimately, is where the power of UNITED 93 lies.