United 93 is a 2006 film written, co-produced, and directed by Paul Greengrass that chronicles events aboard United Airlines Flight 93, which was hijacked during the September 11 attacks. The film attempts to recount with as much veracity as possible (there is a disclaimer that some imagination had to be used) and in real time (from the flight's takeoff) what has come to be known in the United States as an iconic moment. According to the filmmakers, the film was made with the cooperation of many of the passengers' families, though not all agreed to participate. United 93 premiered on April 26, 2006 at the Tribeca Film Festival in New York City, a festival founded to celebrate New York City as a major filmmaking center and to contribute towards the long-term recovery of Lower Manhattan. Several family members of the passengers aboard the flight attended the premiere to show their support. United 93 was later parodied by the short United 300. The film opened nationwide in North America on April 28, 2006. Ten percent of the gross from the three-day opening weekend was promised toward a donation to create a memorial for the victims of Flight 93. United 93 grossed $31.4 million in the United States, and $76.2 million worldwide.