A UK runner has become the first woman to finish the gruelling Barkley Marathon.
The hellish marathon is 100 miles long with 60,000 feet of ascents and descents, which is the equivalent of going up and down Mount Everest twice.
British contender Jasmin Paris has become the first woman to cross the finish line, doing so with just under 100 seconds to spare.
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Paris, 40, successfully completed the five loops around Frozen Head State Park in Tennessee on Friday.
Although she collapsed at the finish line, Paris told BBC News that she was 'overjoyed' with her accomplishment.
She told the BBC: "I only had like a few minutes to get up that hill. So I ended up sprinting at the end of the end of 60 hours of burning through the forest, which felt really hard."
So, we know it's not for the faint of heart.
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But what does the race entail and how do you get involved?
The application process
Applicants need to send over a form to the director of Barkley Marathon, Gary Cantrell.
Simple enough start, right?
Well, it is made trickier by the fact there's no physical or email address listed on the marathon's website.
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Out of the thousand that manage to get through, 40 receive a personal letter from Cantrell.
Not so much wishing them luck as it's a letter of condolences.
Why?
Because certain runners have been chosen as 'human sacrifice'.
Nobody would be under any illusions about what they're getting themselves into.
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Successful applicants have to seal their place in the race, by sending in $1.60, a license plate from their home state or country, a specific piece of clothing or one pack of Camel cigarettes.
How the marathon starts
Before the marathon, runners are presented with a cake that reads: 'Good luck, morons'.
Runners aren't told when the race is beginning, and are kept on high alert from noon to night.
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They only get the go-ahead to start running once a race official lights a cigarette.
In fairness, they get an hours warning - when a conch sounds.
The course
The Tennessee running route is unmarked, leaving contestants to fend for themselves with a map and compass.
The competitors have 60 hours to complete the grueling task.
To prove they've completed each of the loops, runners must find hidden books at various points and rip off a page that corresponds with their bib number.
Finishing the marathon
Since the race began in 1986, only 17 out 1,000 participants have successfully finished the race within 60 hours.
Although other women have completed the Barkley Fun Run, which is three loops under 40 hours, Paris is the only one to have completed the fourth loop.
Ben Thompson