Ultramarathon runner Stephanie Case has made history by becoming the first woman to complete the extreme 100-mile (160km) race in Antarctica.
The event, called the Antarctic Ice Ultra, is held at Schirmacher Oasis, Queen Maud Land, East Antarctica. Participants need to complete 38 laps on a 4.2-kilometer long track.
Keys, 43, traveled with the penguins during the competition and faced strong winds and freezing temperatures as low as minus 35 degrees Celsius. Organizers said it was the coldest conditions the event has ever seen. She finally completed the event in 17 hours, 31 minutes and 39 seconds, ranking second overall.
Due to bad weather, the organizers decided to advance the race to 1am on Sunday. Keyes said that this event not only tests performance, but also survivability.
She told BBC Sport: "If you're just in that environment for 20 minutes, that's fine. But when you're in there for 17 hours or more, it takes a huge toll on the body because you have to expend a lot of energy to keep yourself warm."
She added: "The key is that you have to run fast enough but control yourself not to sweat, because once you sweat, it can be very dangerous."
"Sweat will make you feel cold immediately."
"Going to the toilet is a real challenge"
The challenge is extremely cruel. There is sunshine 24 hours a day in Antarctica. Only a few people try this event every year, and even fewer people finish it.
A total of eight runners participated in the 100-mile event this year, but only four successfully crossed the finish line.
This challenge has always been reserved for men only. There were three women on the starting line this year, but Case, from Canada, was the only one to finish the race.
However, as a self-proclaimed "mountain goat," Case had one challenge he never thought of before: going to the bathroom in extremely cold temperatures.
"If it's on a mountain trail, you can usually just go into the woods and deal with it, but because Antarctica has strict biosecurity regulations, you can't leave any traces," she said.
"And going to the bathroom is inherently difficult when you're wearing heavy clothing. Even if you take off your gloves for just five seconds, you could be at risk of frostbite on your hands, so it's really a challenge."
"The environment there is very harsh and a lot of things can go wrong in an instant," she said.
"When I crossed the finish line, the biggest feeling was actually a sigh of relief, because I really did it, and the result made me very proud."
"All the emotions came out at once."
Human rights lawyer Stephanie Case crossed the finish line 29 minutes behind Chinese runner Ni Yusheng. Ni Yusheng not only won the championship, but also pushed the world record he set last year by more than five and a half hours.
In addition to making history, Case originally aimed to break the world record, but she knew that to beat Ni Yusheng, who has completed more than 500 ultramarathons, she would face "an extremely difficult challenge."
"Sometimes I was only 60 seconds behind him, and sometimes I was only about 200 meters behind him," she said.
"It was really a race. But every time he saw that I was about to catch up, he would look back and immediately speed off."
"I think we really pushed each other to do our best. I'm very proud of my results."
Case became an internet sensation last year after winning an ultra-marathon in Snowdonia, Wales, by breastfeeding her daughter, Pepper.
Although most of the outside world responded positively, she said that some of the criticism was one of the reasons that prompted her to accept this challenge, hoping to prove that "becoming a mother is not the end."
She pointed out that completing this feat in a place that has been described as a "womanless continent" in the past is more symbolic.
