Paul Alexander, a polio survivor who became known as "the man in the iron lung" died on Monday, aged 78.
He contracted polio as a boy, leaving him paralysed from the neck down.
Unable to breathe on his own, Paul was placed in a metal cylinder known as an iron lung, where he would spend the the majority of his life.
He would later go on to earn two university degrees, practice law for 30 years, write a memoir and, in the last few months of his life, become a social media star on TikTok.
Here's a look back at his extraordinary life.
Caught up in an outbreak of largely forgotten disease
Paul contracted polio when he was six years old.
Polio — short for poliomyelitis — is a virus that has been eradicated in many countries, with Australia officially declared polio-free in 2000.
More than 20 years on, the disease is relatively unknown to younger generations.
But in 1952 when Paul contracted the virus, theUS was in the midst of its worst polio outbreak in history.
The World Health Organization (WHO) statistics show more than 3,000 people died from polio in the US the same year Paul caught the disease.
Polio is a highly contagious viral infection that invades the gastrointestinal tract and nervous system.
One in 200 polio infections leads to permanent paralysis, the WHO says.
Of those, it's estimated 10 to 15 per cent die when their breathing muscles become immobilised.
Paul could have been one of them.
But when his condition deteriorated, a doctor performed a tracheotomy — when a slit is cut in a patients' neck to allow for breathing tube to go in — to save his life.
He was put into a negative-pressure ventilator — better known as an iron lung — to keep him breathing.
Not only was he paralysed from the neck down but thetracheostomy meant he was unable to speak.
The tracheostomy was temporary but Paul has relied on a machine to breathe for him ever since.
He holds the Guinness World Record for the longest period for a person to make daily use of an iron lung.
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What is an iron lung? How does it work?
An iron lung is a breathing machine, which has since been replaced by modern ventilators.
It'sa long, air-tight metal chamber, which a patient lies inside with only their head poking out.
With a few windows on the side to people to care for the patient inside without opening the sealed chamber, it looks a bit like a submarine.
Air was pumped in and out it, which changed the air pressure inside.
The changes in air pressure forced air in and out of the patient's lungs in a process calledexternal negative pressure ventilation,theUK's Science Museum website says.
When air was sucked out, the patient's lungs would automatically expand with air — effectively breathing in.
Then air was blown in, the pressure would cause the lungs to deflate — breathing out.
"The rhythmic ‘whoosh’ of air from the iron lung became the reassuring sound of patients breathing," the museum says.
These machines were typically only used by a patient for a few weeks or months until they could gradually recover.
But fortunately they were built to last because some patients— like Paul— depended on them for decades.
Could he leave the iron lung?
While Mr Alexander spent much of his time in the mechanical respirator, he was not completely confined to it.
In his early years, he learned a technique called 'glossopharyngeal breathing', otherwise known as 'frog breathing'.
It was a technique that required Mr Alexander to gulp air into the lungs using his lips, tongue and throat as the main pump.
This gulping action looks like a frog gulping, hence the nickname.
To motivate him, he was promised a puppy if he managed to frog breathe for three minutes.
That's where he got the name for his memoir Three Minutes for a Dog: My Life in an Iron Lung.
It took him a year to master this skill, he wrote.
And after three years of practice, he was able to leave the iron lung for a few hours at a time in a wheelchair.
He became a lawyer
At 21, Mr Alexander became the first person to graduate from a Dallas high school without ever physically attending a class.
He graduated with almost straight A's.
After repeated rejections for two years, he eventually was offered a place at Southern Methodist University in Dallas and later, went to law school at the University of Texas at Austin.
In a video on his TikTok account, which he set up in January this year, Mr Alexander explained how he managed to make it through such an intense area of study.
"I was confronted by a couple of problems that turned out to be major problems, and that was I can't write," he said.
"That means I can't take notes.
"And I couldn't record, cause it takes way too long to listen when you're getting ready for your exam.
"So right off I had to decide how to handle all of the work and the information which is massive.
"What I did was I got my mind ready, I listened very carefully, and remembered what I heard.
"That was a lot of concentration, but yet I found it to be the most effective and rewarding process amongst all of them."
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When the time came to take the exam to be admitted as a lawyer, he wasn't able to use his iron lung.
So he "frog breathed" his way through the gruelling exam in his wheelchair.
Mr Alexander explained that this was "the least laborious" of all the "dreadful" options he had to sit the test.
He passed the exam and went on to become a lawyer in Dallas and Fort Worth.
He would represent his clients in court in a modified wheelchair that held his paralysed body upright.
Then he'd return to the machine.
He ended up working as a lawyer for 30 years.
"You can't believe how many people walked into my law office and saw my iron lung and said: 'what is that?'," he told the Guardian in 2020.
He wrote a memoir with his mouth
It took five years for Mr Alexander to write his 155-page memoir.
"I wrote the book with my mouth and a pencil typing away at a computer," Mr Alexander said on TikTok.
"It was the first book I've ever written and it was kind of a major thing in my life.
"The incredible part of doing it was that it took off all over the world, all the way from Russia, Belize, and Europe, and now millions of people know my name today."
Why did he stay in the iron lung?
Iron lungs are a rarity in 2024.
The ventilators most commonly used today are much more compact machines which typically sit by a patient's bed and can be wheeled around.
While they don't encase a patient, they can be quite invasive.
"Artificial or mechanical ventilation involves sedating a patient, placing a tube into their airway, and using a mechanical ventilator to push air in and out of their lungs,"Melissa Preissner and Stephen Dubsky explained in an article for Monash University.
Generally, this is a temporary measure.
A more permanent option allowed a patient to be conscious, however, it required the breathing tube to inserted via a hole in their neck.
But this technology wasn't available when Paul was young.
And by the time newer machines were developed, he'd grown accustomed to his "old iron horse".
The breathing technique he mastered allowed him to spend part of his day outside the iron lung, he said.
Paul "never wanted a hole in his throat again", according to The Guardian.
However, in his last few years, he had been almost permanently confined to the machine.
"As he got older he had more difficulties in breathing outside the lung for periods of time so he really just retired back to the lung," longtime friend Daniel Spinks said.
While there have been countless medical advancements in the decades since his diagnosis, there's still no cure for polio.
But thanks to intensive global vaccination campaigns, the disease has been largely kept at bay for decades.
This was a cause Paul championed and still spruiked online in his final months.
He became a TikTok star in his 70s
Paul only began posting videos on TikTok this year.
He tagged himself as "Polio Paul" and called his account "ironlungman".
In less than three months, his account amassed nearly 400,000 followers.
And even after his death, his videos continue to reach millions.
As of Friday evening, his videos had attracted more than 6 million likes.
Remembered as a 'bright star'
Paul's brother Philip Alexander said he was someone who "commanded a room" in a statement posted to social media.
"It was an honour to be part of someone's life who was admired as he was," he wrote.
"He touched and inspired millions of people and that is no exaggeration.
"He loved good food, wine, women, long conversations, learning, and laughing."
Mr Spinks said Paul's positivity had a profound effect on those around him.
"Being around Paul was an enlightenment in so many ways," he said.
"He was just one of the bright stars of this world."
Fans also took to social media to express their condolences.
"Forever rest easy Paul Alexander, you were the most inspirational person I have had the enjoyment of following forever fly high,"one TikTok user wrote.
"You were extremely inspirational and you honestly helped me change my perspective on life, you really will be missed," another said.
