For a decade the men and women on United Airlines Flight 93, who died foiling what would have been the fourth 9/11 attack, have been largely forgotten. This weekend, that could finally change.
On Saturday, phase one of a national memorial to the 40 passengers and crew of the hijacked Boeing 757 will be dedicated on the field outside rural Shanksville, Pennsylvania, where it crashed at 10:03 am on September 11, 2001.
Then-president George W. Bush and his predecessor Bill Clinton are scheduled to attend the event, a highlight of the 10th anniversary of the Al-Qaeda assaults that changed a nation and the world.
Nightfall will see the solemn lighting of more than 2,900 luminarias in Shanksville, population 245, in memory of all the victims of 9/11.
Then, on Sunday, President Barack Obama will join a commemorative service in Shanksville, followed by wreath-layings and musical tributes across the 1,000-acre (400-hectare) landscape around the crash site.
Notwithstanding a Hollywood movie, "United 93," and two television dramas, the story of Flight 93 has, over time, been largely overshadowed by the World Trade Center and Pentagon attacks.
Conscious -- after in-flight calls to loved ones -- of the New York attack, the passengers and crew of Flight 93 rose up against the four hijackers, battling them for control of the plane, in-flight recordings revealed.
The plane then crashed in a fireball and plume of smoke at 10:03 am, hitting the ground at 563 miles (906 kilometers) an hour -- a mere 20 minutes' flying time from Washington and its presumed target, the Capitol building.
For years, a home video taken minutes after the crash had been stashed away, only coming to light in the past week, revealing in its raw simplicity the horror of that morning.
"This is the remains of an airplane crash over on Lambertsville Road," says the local resident who took it, Dave Berkebile, by way of narration from behind the camera at his home.
His slightly shaky image shows a plume of smoke and a solitary puffy black cloud hanging listlessly in a clear blue sky over the rolling hills of southwestern Pennsylvania.
"Probably had a terrorist bomb on board that blew up," he said, almost matter of factly. "Don't known anything more than that -- that's what I heard on the (police radio) scanner."
"They ran one into the Pentagon and into the World Trade Center, and we were watching it on TV, and then this one happened... A great big black cloud just mushroomed right up into the air."
Berkebile died in February this year, leaving behind his video as the only one known to exist of the crash of Flight 93. Its existence came to light last week through the Tribune Democrat newspaper of Johnstown, Pennsylvania.
"Listening to it, it's very clear he doesn't know what was going on -- none of us knew what was going on," Tribune Democrat city editor Arlene Johns told AFP by telephone.
Berkebile had offered his video to television outlets, "but they either didn't even look at it or just rebuffed him... so he thought it wasn't of very much consequence and basically put it away and forgot about it," Johns said.
In 2006, he gave it to another local, Val McClatchey, whose still color photograph of the same dark cloud, seen behind a red barn, has been an object of fixation for conspiracy theorists who insist that the crash was a hoax.
McClatchey held on to it for another five years, Johns said, not revealing its existence until after Berkebile's death for fear he might be subjected to the same unwanted attention that she has endured from Flight 93 skeptics.
The memorial to be dedicated on Saturday comprises a "field of honor" that gently descends to the crash site and a visitors plaza.
Future plans call for a memorial wall by 2014, a grove of 40 trees and, in time, a 93-foot (28-meter) "tower of voices" comprising 40 wind chimes.