Ask the average person to attempt to describe the events of September 11th and they will tell you that one plane flew into the North Tower (American Airlines Flight 11), one plane flew into the South Tower (United Airlines Flight 175), and one plane flew into the Pentagon building (American Airlines Flight 77). Those who believe conspiracy theories may tell you that these three planes were not planes at all, but missiles disguised as planes, a few people may bring WTC building seven into the equation which was brought down without any obvious external impact. Very few will mention the fourth plane, United Airlines Flight 93.
Flight 93 was also hijacked by terrorists, four Al-Qaeda operatives, but it crashed into a field in Pennsylvania after a fight by passengers and the crew to regain control of the plane. Although all 44 people on board were killed upon impact nobody on the ground was injured. The flight was en-route to San Francisco from Newark, but the hijackers intended target remains unknown. The CIA have suggested that the fourth target may have been the White House, but this isn’t certain.
Flight 93: The Flight That Fought Back is a feature length docudrama commissioned by the Discovery Channel which was first screened in the United States on September 11th 2005, it was also aired on national television in the United Kingdom, Japan, Germany, Russian, and Ireland. Discovery donated profits from the film towards a permanent Flight 93 National Memorial which is now located on the site of the crash in Somerset County, Pennsylvania. Also worth a watch is Flight 93: The Flight That Fought Back (2002, ITV).