Round-the-world runner Rosie Swale Pope has set out on the most dangerous and challenging leg of her journey just five days before Christmas.
Rosie Swale Pope set off on her run from Tenby on 2 October 2003
The adventurer from Pembrokeshire will face temperatures of -60 Celsius as she runs across Eastern Siberia.
The 58-year-old from Tenby has been resting in a hotel at Ulan Ude but hit the road again on Monday after being granted a visa to enter Mongolia.
It is 15 months since she set out to circumnavigate the globe on foot.
She has taken on the challenge to raise funds for a Russian children's home in Kitezh, and to increase awareness of The Prostate Cancer Charity after the death of her husband Clive Pope.
Liza Hollingshead of the Ecologia Trust, which runs the children's home, said: "She is now starting on the most challenging part of the journey. Eastern Siberia is very remote, very cold and very empty."
Her route will take her to Chita and then on to Yakutsk, one of the coldest places on earth.
"It is a struggle for survival. Lighting her stove is a huge undertaking in the cold," added Ms Hollingshead.
"Breathing at -20 Celsius can be painful. That's the temperature now and it will get colder, down to -60 Celsius.
"As long as she keeps moving the cold is not too bad. The danger is when she stops for the night that she might get covered in a snowdrift or simply go to sleep for too long and freeze."
The runner has suffered a few set backs on her massive run which started in west Wales in October 2003. She was held at knife-point during an attempt to steal her satellite phone.
She also had to go to hospital for minor injuries after being hit by a bus where she was told she had pneumonia.
But after resting Ms Hollingshead said Rosie was enthusiastic to continue.
"Rosie is missing her friends and family at home but there is still a long way to go and the next six months will be the hardest, especially the mountainous road to Yakutsk," she added.
"From there to Magadan it is apparently not too bad. From Magadan it is uncertain whether she will run the Bering Straits or fly to Alaska and continue the run from there."