It’s almost 20 years since the September 11 attacks but for many survivors, the pain and trauma are still raw.
Some were left with life-changing physical injuries, while many still struggle with the mental torment caused by the events of that day.
One of the most severely injured survivors, Lauren Manning, suffered burns to more than 80% of her body.
“By any medical standard, I should have died,” she tells Sky News.
Lauren had just entered the World Trade Center’s North Tower when the first hijacked plane crashed into the building, sending a fireball hurtling down a lift shaft and into the lobby.
“There was this incredibly loud, piercing, whistling sound and an instant later I was engulfed in flames,” she says.
“The pain was incalculable, crushing, penetrating deeper and deeper.
“I was burning alive. There are no other words for it.”
As Lauren fought against the flames, she ran outside and across a road before dropping and rolling on a grass embankment where a man tried to help her.
“I didn’t fall down and die in a heap of flames – I struggled against them,” she says.
“I was screaming to him: ‘Get me the hell out of here!'”
As she lay severely injured, Lauren watched in horror as terrorists smashed a second plane into the World Trade Center’s South Tower.
She saw people fall from the skyscrapers, knowing that her colleagues from financial firm Cantor Fitzgerald were trapped on the upper floors.
All of the company’s 658 employees in the office on September 11 were killed that day.
On the ground, Lauren – who had previously escaped the 1993 bombing of the World Trade Center – managed to find an ambulance but her chances of survival were slim.
“The burns were extraordinary,” she says.
“It burnt 82.5% (of my body), most of it third-degree.
“More than 20% was fourth or fifth degree, which means you lose the muscle or the bone – so various amputations (were needed) on fingers on both hands.”
• ‘I was so afraid my son would not recognise me’
Lauren was rushed to hospital and eventually placed in an induced coma before being moved to a specialist burns centre.
Over three months while she was in a coma, her husband Greg would read Robert Burns poems and play music from their dating days.
“Perhaps it had an impact on me, knowing I was loved,” she says.
“My parents drove hours and hours expecting me to be dead – and they were there every day.”
Several days after waking from her coma, Lauren’s then one-year-old son Tyler visited her for the first time since the attack.
“I was so afraid that he would not recognise me,” she says.
“He came down the hall and there he was walking. A beautiful little soul.
“He did not recognise me at first…. but he came back towards me and he recognised me, I guess through the eyes and the voice.
“That was everything I needed.”
Lauren spent more than six months in hospital but her recovery – which involved several operations – took nearly 10 years.
“You get burned – which is probably the most sadistic form of human torture – and it takes years and years,” she says.
Lauren, whose second son Jagger was born in 2009, still has contact numbers listed in her phone for many of her colleagues who died on 11 September 2001.
“The notion of the murders and the terror and the death are never far away,” she adds.
• The fire official who narrowly escaped Twin Tower collapse
Lynn Tierney arrived at the World Trade Center after both planes had hit the Twin Towers.
The deputy commissioner at New York City’s fire department had been due to attend a job interview on the 68th floor of the North Tower that morning – but her plans had been drastically changed by the terror attacks.
“It was a horrific scene outside,” she says.
“Both towers were burning… it was engulfing the upper floors.
“But in addition to the flames, the worst thing was there were people jumping (from the towers).
“I saw a couple jump with their hands together. That was unbelievable.
“It continued the whole time we were in the lobby. You could hear it. It was a terrible sound.
“I can’t imagine the choice they were faced with. I was just thinking about their families. It was just horrific.”
Lynn had travelled to the scene with 12 firefighters from two different units – all of whom later died during the rescue effort.
She walked into the lobby of the North Tower through a window after the exploding jet fuel had blown out the glass.
But at that point, fire chiefs had already determined they wouldn’t be able to put out the flames.
“The mission became purely rescue, to try to go up and get out as many people as possible,” she says.
Lynn was working to help coordinate the rescue effort from the north side of the North Tower when suddenly the South Tower collapsed.
• ‘The dust was so thick you could almost chew it’
She says she “ran like hell” and jumped into a loading dock about 80 yards away.
“The dust was so thick you could almost chew it,” she says.
“It was gritty so you couldn’t take a breath up your nose or anything.
“I was having trouble breathing. Everybody was.”
After entering the loading dock, Lynn says a police inspector tried to shield her with his body.
“That’s the only time I thought about dying,” she says.
“I just thought: ‘God, just let it be fast.’ I don’t want to linger in here like a miner for 18 days and be crushed at the same time.”
After getting to safety, Lynn was in New York City Hall when the second tower collapsed, about two blocks away.
The force of the building collapse blew the hall’s doors open and as smoke and dust came into the building, Lynn hid in a staircase.
Some 343 firefighters died that day and Lynn wrote about 100 eulogies for the victims.
On one day alone, 23 funerals were held.
“These emotions from 9/11 are always under the surface,” says Lynn, who later became president of the 9/11 Tribute Centre and held the role until 2007.
“You learn to live with it. I call it ‘keeping a bolt in your heart’.
“It’s overwhelming sometimes. The oddest thing for me is I lived through it.
“I can’t believe I got out of there. That’s the biggest surprise.”
• The British trader who felt Twin Tower plane crash
Briton Charlie Gray thought an earthquake had hit New York when he was working in the North Tower on 11 September 2001.
The London-born trader, who was employed by broker firm ICAP, was stood in the office on the 26th floor when the building “shook and moved”.
Suddenly, he saw debris falling from the upper floors.
“You could see this stuff was really burning,” Charlie tells Sky News.
“We thought it must be something like a bomb.
“Nobody had to tell us. Everybody just headed for the stairs.”
Charlie and his colleagues began walking down the tower but they were slowed down as more and more people entered the stairwell, before they passed three firefighters on the 17th floor.
“As they passed us we heard on their radio another plane has hit the South Tower,” Charlie says.
“It had taken about 17 minutes to get down nine floors.”
• ‘It was like a warzone’
Charlie describes the scene outside the World Trade Center as “like a warzone”.
He says he saw body parts on the street and cars that had been destroyed by falling debris.
A “black charred body” landed about 30ft away as he walked to the ferry terminal and he watched 20 people jump from the towers, he says.
“What was their option?” Charlie asks.
“You stand and either die of smoke inhalation, you burn to death, or you take that quick leap and get it over with.”
After boarding a ferry, Charlie “heard a rumble” and watched as the South Tower came down.
“In less than a minute, the dock where we were just standing was a mass of dust and dirt,” he adds.
Charlie says 20 of his friends were killed that day – including one he saw in the lobby of the North Tower shortly before the first plane struck.
He says a psychiatrist later diagnosed him with a form of PTSD called “guilt disorder”.
“I was having trouble getting my head around why so many people died and I didn’t,” Charlie says.
After moving back to the UK in 2016, he now gives motivational speeches but admits he still sometimes struggles with the emotional toll of 9/11.
“I get a little teary now and again,” he says.
“I think about things and get a little bit upset because it was an awful day.
“It will never go – that monkey will always be on my back.
“But I found talking about it and sharing my experiences with people helped me get through it.”