What does someone who has scaled the highest mountain on each of the seven continents do next?

Ms Jane Lee decided to cross 560km of icy Greenland on skis, which she did last month with her friend, Ms Lee Li Hui.

The two are believed to be the first Singaporeans to achieve the feat, but it is not the first time they have blazed trails.

In 2009, Li Hui became the first Singaporean woman to reach the summit of Mount Everest, part of the all-female team led by Jane. Two years later, Jane was the first South-east Asian woman to scale the highest summits on each of the seven continents.

Greenland, a country a quarter the size of the United States with only 57,000 inhabitants, was chosen next because it "had the mystery of being less visited, and we liked the idea of crossing a whole island", said Jane, 29.

Only 40 people try to ski across it every year, added the recent MBA graduate from Yale University.

The plucky duo trained for their month-long expedition by running 20km a few times a week and climbing stairs with 20kg packs.

They landed on May 5 in Kangerlussuaq, a western coastal town near the base of the Greenland ice sheet. From there, they skied for more than 20 days in temperatures of minus 20 deg C and below.

Each day, they rose at 5.30am after five to six hours of sleep, melted snow for drinking water and dismantled their campsite. They skied from 8am to 8pm, while hauling two 30kg sleds each.

Meals consisted of oats, rations and high-calorie food like crisps and chocolate.

Whiteout, a weather condition in which the horizon cannot be seen, was mentally exhausting.

"There were no landmarks, no animals, nothing, just a sea of ice and sky. It was a mental challenge to stay focused and follow my compass point," said Jane.

But they powered on. She explained: "It's really your mind that takes over. You just refuse to give up. Your body adapts because you have no choice."

Their cross-country journey took them through a foreign and surreal environment. An arctic sparrow was the only animal they saw, though one of the two teams they met along the way had seen polar bear tracks.

Luckily, they did not encounter any deadly piteraqs - extremely strong winds of up to 80 metres per second which can kill.

There were moments of beauty, too. "Sometimes when the sun shines and the snow glitters, it really looks like diamonds," said Li Hui, 31, a senior insurance executive.

They kept their family and friends back in Singapore updated through messages from their satellite phone, which they could also use to call for help.

But they never did, not even when Jane's right knee "popped out at a very weird angle" - twice. "I literally could not move my entire leg. Li Hui had to grab my leg and slowly straighten it. It was excruciating," recalled Jane.

Later, she found out from a doctor that it was because her muscles had been so tight from all the skiing that they "pulled the head of one of my bones out of the socket".

They kept on skiing.

To avoid getting blisters from their skiing boots, they fashioned makeshift insoles from their foam sleeping mats. "Eventually we cut out so many insoles that our sleeping mats were getting smaller and shorter," recounted Jane.

They reached the east coast and the end of their journey on the 25th day, stopping awhile at the small village of Isortoq.

There, they had a memorable meal with an Inuit family, whose way of life included hunting and eating polar bears and narwhals.

"We thought it was such a strange way for a ferocious predator to end its life, in a bowl of instant noodles," said Jane.

The team was fully sponsored by private Swiss bank Julius Baer. Said its Asia-Pacific region head Thomas Meier: "The similarities between outdoor adventure and business - the way one deals with difficulties and plans to succeed in any quest - is a culture we want to instil in our employees in Asia."

They returned to Singapore on June 7, to home-cooked meals with family. Neither has anything concrete planned next.

Said Jane: "Adventure exploration will always be a part of our lives. But for now we're enjoying being back in Singapore, where we don't have to wear five layers of clothes."