It has become routine for modern explorers to tag an educational component on to their journeys, in order to attract funds and boost their credibility as people doing something for the common good.
Ann Bancroft and Liv Arnesen do it differently. Two years ago, these former teachers, a 48-year-old American and a 50-year-old Norwegian, became the first women to traverse the Antarctic landmass. They skied, ski-sailed and pulled 250lb sleds for 1,700 miles across rutted ice-sheets and glaciers.
Their next target will be to cross the Arctic sea.
Woven into their approach to these huge challenges is the idea that their expeditions must be used to educate pupils, to raise their aspirations, and to bring classrooms around the world closer together. "It's our mission," says Ann Bancroft. "It's what gives our lives purpose." "Without it there would be no point," says Liv Arnesen. "We'd just be traipsing about."
The result is two detailed online curriculums, with carefully worked-out lesson plans, which schools can download. "Educators will take what's there and build on it," says Ann Bancroft. "Teachers are the most creative people in the world."
One curriculum explores all aspects of the polar world, from climate change to nutrition to frostbite. The second is designed to encourage children to pursue their dreams, by guiding them through goal-setting and aspiration-building. The women see themselves as "just ordinary women" and believe that if children can see what people like them have achieved, it can spark their hopes and fuel their determination. "They can also look at us and see that your passions aren't necessarily easy. They aren't instant.
If you want to do it, you have to work at it," says Ann Bancroft.
To bring all this alive they made regular website transmissions and satellite phone calls from the ice - not easy when you have to put the phone and batteries inside your clothes to thaw them out - with the result that three million children in 116 countries were able to follow their progress. Their book contains testimonies from teachers in Norway, South Africa and Taiwan about what this journey meant to their pupils.
"We live in the tropics," writes a Taiwanese teacher, "so they don't see snow or ice. Antarctica was a place beyond their imagination. It also put them in touch with global issues and children around the world." And, she adds, gave them the determination to rebuild their lives following an earthquake that destroyed many schools. A Norwegian teacher writes about how his middle-class pupils began to exchange e-mails with other schools about what they wanted from life, and how humbled they were when a Palestinian boy told them his dream was "to go to England to study and then return to his village and use his education for the benefit of his local society."
"We were more than satisfied," says Liv Arnesen. "It was fantastic that so many people were involved."
The link worked both ways. The women's journey was dogged by bad luck. In order to complete it before winter set in they needed to ski-sail much of the way. But the wind wasn't there. When they were finally forced to abandon the last leg of their journey across the Ross ice shelf, their disappointment was bitter. But a phone call to a classroom in Minnesota lifted their spirits. They could feel the children's awe at the fact they were speaking directly to Antarctica, and were moved by the way their journey had touched them. No one wanted to end the call, which lasted 40 minutes, and after that the lost final 400 miles seemed like nothing compared to the way they had touched children's lives.
"And you know what? Kids are so resilient," says Ann Bancroft. "We didn't want to let them down, but they were the ones who told us it's okay. You did your best. They have so much wisdom in their approach to life."
In their book, the two women talk of the importance of their own teachers.
Ann Bancroft, who struggled with dyslexia at school, pays moving tribute to the women who inspired her.
They now spend a lot of time speaking in schools and colleges, passing on the baton. They field the inevitable questions - how did they go to the bathroom in Antarctica? ("fast"); how did they know when they had reached the South Pole? ("there's a marker") - and encourage their listeners to pursue big dreams.
"There was one girl recently who said she was going to try and go to college after she heard us," says Arnesen. "None of her family had gone to college, she didn't have that sort of background at all, but I guess she thought if these crazy women can do what they do, then I can do this."
No Horizon Is So Far by Liv Arnesen and Ann Bancroft with Cheryl Dahle (Da Capo Press pound;16.99)Ann and Liv Cross Antarctica: A Dream Come True (for ages seven to 12) by Zoe Alderfer Ryan, illustrated by Nicholas Reti (Da Capo Press pound;12.50)www.yourexpedition.com