There have been dozens of screen versions of the September 11th attacks in New York in 2001, including fictionalised attempts from filmmakers like Paul Greengrass and Oliver Stone.
But a new six-part series on National Geographic, 9/11: One Day in America, is looking to go even deeper into the terrible events of that day.
Using a mix of never-before-seen archive and first-person testimony, it pieces together the collapse of the Twin Towers in a visceral way.
One of those lending their memories to the programme is Joseph Pfeifer, the first firefighter chief to arrive that fateful morning, who helped set up a command post and also lost his firefighter brother Kevin when the towers fell.
Alongside him that morning happened to be cameraman Jules Naudet, who was filming a documentary and ended up going into the North Tower with Pfeifer and his team.
“Thankfully, we had Jules with me with a camera inside,” says the now retired Pfeifer. “Otherwise, anyone could have made up [that part of the] story.”
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“I think [Nat Geo] got it right,” he continues, regarding the new shows, which are made in collaboration with the National September 11th Memorial and Museum.
“They were able to take footage from that day and then allowed people to explain what they were feeling at the time.
"And I think by making it personal, rather than a news broadcast, getting inside people’s thoughts and their hearts, becomes really important.”
Of course, the event is more personal to Pfeifer than most, who has spent the past 20 years talking about what happened that day and how we can learn from it to emergency services, students and the media. The trauma associated with such a global catastrophe can’t have made that easy.
“I think that we go through a process of resilience,” he says.
“And part of that process is coming together. We see that at memorials – the candles and the flowers and the pictures. We saw that in London with the 7/7 bombings. But then something else happens and that’s telling the story.
"There’s a sense of putting an order to it. There’s a sense of reflecting on the past and then turning towards hope for the future. So the stories are difficult, but they’re also part of my own resilience.”
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But does he mind replaying one of the worst and scariest moments in his life over and over again?
“[People] know my story from the documentaries,” he says.
“And because of that, they wind up telling their own personal story, what it was like for them that day. Where they were, who they were with and what it felt like.
"It’s not like winning an Olympic medal that most people can’t relate to. This was a global event, everyone felt like they were watching it in real life and they have their own stories to tell.”
Of course, now that 20 years have gone by, there is a whole generation of people who have no memory of 9/11. “I lecture at West Point, the military academy,” he says.
“They’re young and they either weren’t born or they were, like, two years old at the time. They don’t have memories from that day.
"But when they see the films, they’re actually going through the event. They experience that in real-time in their life today. And they have really strong emotional reactions to those events.
"So it’s a whole different generation experiencing this tragedy.”
He admits he hasn’t seen films like United 93 and World Trade Center (“I guess when you see the real thing, there’s no sense to go through the other versions”) but having just written a memoir, titled Ordinary Heroes, he is feeling optimistic.
“I chose that title because it explains that day and what we should never forget,” he says.
“And that’s as the firefighters were going in and climbing the narrow stairs of the World Trade Center going up, people were coming down.
"And they were telling people, ‘don’t stop, you can make it out of here, keep going.’ And we know from those simple words, that was the difference between life and death. Ordinary things, but at an extraordinary period of time.”
He wants the National Geographic series to foster a similar sense of positivity.
“My hope is the film will bring people down deep into that day and then bring them a sense of hope, of human beings helping one another at the most difficult time of their lives,” he says.
“However, the question we wrestle with now, in this pandemic, is why are we still fragmented? And I think as we come upon the 20th anniversary, we need to remember how we were together.
"How there was a sense of global unity, because that’s how we got through 9/11 and that’s how we’re going to get through this pandemic. We need to do it together.”
9/11: One Day In America airs in the UK on National Geographic from 31 August.