Twenty-five years after the deadliest terrorist attacks in US history, the story of 9/11 2001 is well-known: Four US passenger jets were hijacked by 19 terrorists with allegiances to al-Qaeda, a militant jihadist terrorist organization.
Two of the jets flew into the World Trade Centre's two towers in New York City killing 2,753 people. The third jet hit the Pentagon in Arlington VA, killing 184 people and the fourth jet, after the passengers and crew fought back against the terrorists, crashed in a field in Shanksville PA, killing 40 people.
That's not the complete story.
In Canada, the story was 38 aircraft diverted to the town of Gander in Newfoundland and Labrador, where close to 7,000 passengers and crew were welcomed and housed by residents.
In addition, 240 flights in Canada were diverted to 17 airports in the country when US airspace was closed.
Behind the story of the closure of US airspace is another, and little known, chapter.
The Federal Aviation Authority (FAA) governs all things pertaining to airplanes, from takeoffs to landings, in the US.
On the morning of Sept. 11, 2001, a man named Ben Sliney arrived at the FAA's command center in Virginia, shaking hands and receiving well-wishes from his colleagues, according to Aviation 24/7 (AV 24/7), an aviation safety awareness and news-sharing platform.
It was Sliney's first day as National Operations Manager of the FAA after 27 years of air traffic control, making him the man in charge of the flow of every flight in the US.
At 8:46 am, the first hijacked jet hit the North Tower. At 9:03 am, the second jet hit the South Tower.
At 9:37 am, the third plane flew into the Pentagon.
"By 9:42 am, Sliney had made the unprecedented decision that altered the course of American history," reports AV 24/7. "Sliney didn't wait for permission. He gave his first order: A national ground stop, meaning no plane, anywhere in the US, was allowed to take off. While ground stops are used locally for bad weather, it had never before been done nationwide."
But even with the ground stop, there were still more than 4,500 planes in the air.
"After the second aircraft hit the building, I didn't know how many more there could be," Sliney later recalled, according to AV 24/7. "There could be 30 of them. I didn't know."
"In the command center, no one above Sliney had ordered anything. No one had told him what he was allowed to do," reports AV 24/7."But five minutes later, at 9:42 am, Sliney spoke loudly, saying "That's it. I'm landing everyone."
Every aircraft flying over the US or flying to the US was instructed to immediately land at the nearest airport, regardless of its destination.
That order sent the airplanes to Gander.
"It was a logistical nightmare that had never been practiced, let alone executed," reports AV 24/7. "Controllers had to rapidly sequence jets into small regional airports that had never handled them. Thousands of passengers suddenly touched down in cities they had never heard of."
It took more than two hours for the 4,500 planes to land, with no accidents.
Sliney later admitted that in the chaos of that morning, it had crossed his mind to question whether he had the authority to ground the entire country.
"He gave the order anyway, deciding to let the question wait," says AV 24/7. "The 9/11 Commission's report officially recorded the life-saving order as his. Five years later, when movie director Paul Greengrass made the harrowing film United 93, he asked Sliney to play himself. He did.