PERITO MORENO GLACIER, Argentina - At 67 years old, grandmother Margot Anderson could be enjoying the quiet retired life at home in England.
Instead, she works a string of part-time jobs so she can afford to be standing at the foot of a pale blue glacier in Patagonia, about to jump into near-freezing water with 53 other extreme swimmers from around the world.
"If this is the last thing I do in life, I'll go with fullness," says Anderson, before plunging into the frigid water off Argentina's Perito Moreno glacier.
Anderson has made the pilgrimage to the remote region at the southern tip of South America along with her best friend, Jacqueline Cobell - who, like her, braves water temperatures of two degrees Celsius (36 Fahrenheit) wearing nothing but an ordinary swimsuit and cap.
"My husband and two daughters think I'm mad," says Cobell, a relatively youthful 60, who set a world record in 2010.
In northern Europe, where winter swimming is more widespread, thousands of participants commonly turn up for such events and competitions.
But just 54 swimmers made the trek to Patagonia for Latin America's first winter swimming festival on August 8.
Cobell and Anderson laugh as they describe their training for the event: filling a bathtub with ice and timing each other with a stopwatch to see how long they can bear to stay in it.
'You against the elements'
Anderson, who has swum all her life, comes from a family of winter swimmers - her father and grandfather also practiced the sport.
Like the other seniors at the festival - in all, six swimmers over 60 took part - her face lights up when she talks about why she does it.
"Sometimes you think, 'Why am I doing this? Why am I going in?' But once you're in the water and it's you against the elements, and the challenge, it just takes over and you want to finish, you want to compete and get out and be fine," she says.
To support her hobby, she works part-time looking after people with disabilities in Kent, in eastern England.
"I should be retired, but I have a little part-time job to pay for my swimming," she says.
She has also worked other odd jobs ranging from swim instructor to dog groomer in order to fund winter excursions to the lakes and rivers of Russia, Finland and Estonia.
Swimming in near-freezing water can cause hypothermia or even cardiac arrest, but that doesn't deter those who love the sport.
They typically have no strict training regimen, said Natalia Szydlowski, an Argentine nutritionist who is writing her doctoral thesis on ice swimmers' physical condition.
They are not professional athletes and have no special diet, but can swim 1,600 meters (5,200 feet) or more in air temperatures of -20 degrees Celsius.
"People say, 'You are mad swimming in ice water,'" says Cobell.
"But after swimming in ice water, you feel accelerated and alive. You feel that you could do anything. And I think that it is good for the heart, soul and spirit." Cobell only took up competitive ice swimming five years ago.
In 2010 she set a world record: the slowest-ever crossing of the Channel from England to France.
"It took me 28 hours, 44 minutes to swim to France, without interruption," she says with pride.
The oldest participant in the festival, 73-year-old Lech Bednarek of Poland, says he hopes more people will discover the exhilaration of the sport.
"I really hope the passion catches on in South America because every time you do it you're reborn," he says.
But the star of the Patagonia festival is Henri Kaarma, who, at 39, is a spring chicken next to Bednarek.
The Estonian is the current world champion winter swimmer. He set a record swimming 2,400 meters in zero-degree water in Siberia.
Discussing what draws him to the sport, he describes an experience radically different from his day job as a credit risk analyst in Tallinn.
"This is one thing where I am in the top of the world, I can probably say that, so why not do it when you're one of the best?" he says.
"I want to find out my limits."