It is all too easy to imagine the ways in which the first major film about the terrorist attacks of September 11, 2001 could have gone wrong. On the one hand, it could have served as wartime propaganda, using the horrific events of that day to paint a mythic portrait of incipient heroism, full of stirring music and bold close-ups on the passengers as they rise to their feet with a cry of "Let's roll!" On the other hand, it could have bent over backward to give the story nuance, putting words in the terrorists' mouths designed to keep their hostages forever in doubt about the rightness of their decision to fight back, a la Steven Spielberg's Munich. But thankfully, United 93—which chronicles the hijacked flight that ultimately crashed into a Pennsylvania field, instead of its intended target in Washington, D.C.—avoids both of these approaches.

Hijacker Ahmed Al Haznawi (Omar Berdouni) prepares to board United Airlines Flight 93

Instead of anything so nakedly artificial, writer-director Paul Greengrass presents the events of that morning with a straightforward, matter-of-fact naturalism, as though he simply happened to have cameras in all the right places when the hijackings took place, catching the events as they unfolded. As with his earlier film Bloody Sunday, which concerned a Northern Irish civil-rights march that was attacked by British troops in 1972, he relies on hand-held cinematography and a cast made up mostly of unknowns to make his reconstruction of an historical event as realistic and documentary-like as possible.

The effect is to let the viewer draw his or her own conclusion from these events. But this is not to say that the film never steers our emotions, or our sympathies. Even though we know how the story will end, we do not know quite how it will get there, and Greengrass builds a fair bit of tension through careful edits and an ominous score, the latter courtesy of John Powell. As passengers and crew prepare for their flight, we see someone refuel the plane, and the word "flammable" is briefly, prominently displayed in the frame; normally, this might be an innocent detail, but in this story, we know exactly what it portends.

Passenger Todd Beamer, played by David Alan Basche, tries to reach home

The film also creates tension by introducing new "facts" that might not have occurred to us before. In one scene, the air traffic controllers can only watch helplessly as one of the hijacked planes, having deviated from its original course, seems to be on an unintentional collision course with another plane. And when the passengers aboard Flight 93 band together to fight back against the terrorists, they check first to see if any of them have the experience necessary to land the plane safely once they have taken it back; we know that they will never get the chance to do so, but for a moment, we hope that they might.

Perhaps most significantly, and daringly, the film creates tension by putting the terrorists at the center of the movie and allowing us to identify with them, sort of. They, after all, are the only ones who know what's coming, just as we who watch the movie know what's coming. As Flight 93 takes off from Newark, New Jersey, the terrorists look out the window at the World Trade Center towers in the distance, and unlike every other passenger on that plane, they know exactly what is going to happen to those buildings within the next half-hour—two other hijacked airliners will crash into the buildings, ultimately leveling them both and killing some 3,000 people.

The terrorists also seem to share our apprehension. One of the reasons the hijackers aboard Flight 93 failed to reach Washington, D.C. may be that they waited too long before taking over the plane, resulting in a much longer flight back east—and Greengrass speculates that the leader may have hesitated to go ahead with the plan, until his frustrated comrades pushed him. Early on, the film even goes so far as to show the leader placing a call to someone and saying "I love you," just as his victims will do. Is Greengrass humanizing the enemy? Of course. But none of the other hijackers is shown doing this—and the film may be suggesting that it was the leader's very humanity that held him back, for a while.

Crew and passengers charge the cockpit to reclaim the plane from the hijackers

The other passengers are treated as a group, more than as individuals; Greengrass is more interested in the social dynamics aboard that plane than he is in any single person, and besides, until the plane is hijacked, the passengers are almost all strangers to one another anyway. It's not even clear which of the passengers is Todd Beamer; when the phrase "Let's roll"—spoken by Beamer, a Christian —is finally uttered, the camera is not looking at anyone in particular, but down the aisle that the passengers are about to rush. Nevertheless, individual persons do stand out. A flight attendant tries in vain to sound reassuring even when things are going very wrong; a doctor tries to attend to a wounded passenger but is forced back into her seat; and an appeaser insists right to the end that they should not fight back because the terrorists will merely hold them for ransom and then let them go. (This passenger speaks with a German accent, so he may or may not represent European opposition to the "war on terror.")

Likewise, the situation on the ground. Greengrass captures the shock and confusion among the military officers and air traffic controllers (several of whom play themselves) as the hijackings multiply, the buildings are destroyed, and the various federal bodies fail utterly to communicate with each other. And while a few faces stand out, it is the broader changes in mood that matter here. Some of the authorities take the first hijacking in their stride, chuckling that hijackings are so costly and old-fashioned; but then things get very serious, and they slowly realize that they are witnessing nothing less than an act of war.

The film does not shy away from the religious dimensions of that fateful day. From the very first scene to the very last, the terrorists pray; and if the passengers don't have much reason to pray until the last section of the movie, the film does hint at the religiosity of the culture from which they come, and foreshadow their own prayers, by noting a "God bless America" sign by the side of the road as the terrorists make their way to the airport.

Jean and Donald Peterson (played by Becky London and Tom O'Rourke) comfort one another

The film is very intense, and it may be too much for some people, especially if they see it in a crowded theatre, and especially if they see it in certain cities. Some people have asked if anybody needs to see this movie. To that, the simple answer is: As with all movies, some do, and some don't. The more important question, and it's a rather different one, is whether this movie needed to be made. And the short answer to that is: Absolutely, yes, it did.

For better or worse, things and people often seem more real to us when they become the subject of a movie, and films are one of the primary means by which we collectively process the world around us. So it would be strange indeed if filmmakers continued to ignore the most pivotal moment in recent history. A portion of this film's revenues will be donated to the Flight 93 memorial fund, and in a way, the film—produced with the support of the victims' families—is itself a memorial of sorts. It honors the passengers who fought back by visualizing their experience and imprinting it on our screens for years to come.