Why do people risk their lives to summit the world's deadliest mountains?

Historian Natalia Mehlman Petrzela explores life, love and death on Earth's second-tallest peak in the new season of Extreme.

Straddling the border of Pakistan and China in the Karakoram mountain range, K2 is often referred to as the "savage mountain". Towering 8,611m and reaching into the heavens like a snowcapped pyramid, K2 is the world's second-tallest mountain (topped only by Everest) and arguably the hardest to climb. In Peak Danger, the second season of BBC's Extreme podcast, host and historian Natalia Mehlman Petrzela chronicles the harrowing tale of newlyweds Cecilie Skog and Rolf Bae, who scaled K2 in 2008 – and found themselves in a disaster that would see 11 climbers lose their lives in two days.

For Skog, the allure of the mountains came early. She was born surrounded by formidable peaks and explains that even as a child, she often found herself drawn to the alpine heights all around her. Like many climbers, she called the rush of scaling mountains "addictive".

"I grew up in Ålesund, a little town on the west coast of Norway, and surrounding this little town is mountains everywhere. It is really beautiful there," Skog says on the podcast. "These mountains, they should have given it with, like a warning sign: 'this is really addictive.'"

While climbing mountains all over the world, Skog also found love and married climber Rolf Bae. After years of honing their skills, the couple decided their honeymoon would be the perfect opportunity to venture to Asia and attempt to scale K2. Their journey started in Pakistan at the Baltoro Glacier, a near-mythical landscape home to six peaks over 7,900m. The beautiful, nearly untouched scenery is one draw, but it is accompanied by the thrill of high altitude, steep cliffs and breathtaking ascents – and the always-present spectre of cheating death.

"If you are going to take on K2, you got to be at the top of your game. That is why it is known, in climbing circles, as 'the mountaineer's mountain,'" Petrzela says. That reputation was something Skog and Bae were well aware of, as well as the inevitable possibility of facing a life-or-death emergency.

"The most important thing cannot be to summit; the most important thing has to be to come back home alive," Skog says in the podcast.

Upon their arrival to the Karakoram Range, Skog and Bae joined some 30 hopeful, optimistic climbers from far-flung countries such as Serbia, Ireland, France, the Netherlands and South Korea, as well as a team of Nepalese and Pakistani porters. They were experienced and knowledgeable about the conditions, the dangers and the possibility of inclement weather. Avalanches, rockfall and unpredictable blizzards weren't unheard of – but there was another sign: a memorial at the beginning of the journey dedicated to those who had lost their lives while attempting to scale K2.

"When you arrive, you see a huge pile of brown, weathered rocks, all stacked on top of one another. It is adorned with crisscrossing flags, and pictures of fallen climbers," Petrzela says.

The memorial isn't enough to deter climbers, nor is the low oxygen level and bitingly cold temperatures.

"What I experienced was: 'why am I here… am I in the right place?' I questioned myself. I questioned my motivation for being there," fellow climber Dr Eric Meyer says on the podcast. "And then you start to reflect on… is it worth the risk?"

It has never been easier for intrepid travellers to challenge themselves and face K2. Petrzela explains on the podcast that a cottage industry has materialised and offers all the necessities for anyone hoping to be among the few who can say they've summited the mountain. However, that commercialisation has led to concerns over climbers' safety and the sometimes-laissez-faire approach to what is undoubtedly a very dangerous trek.

"There is no rulebook to mountain climbing. No international association telling you what or how to climb. And there is nothing to stop anyone from making mountaineering into big business. Nowadays, for the right price, you too can buy your way onto the slopes of an 8,000m peak," Petrzela says. While there is no association overseeing all climbers, there is the International Climbing and Mountaineering Federation (or UIAA), which "developed standards for over 25 types of safety equipment, including helmets, harnesses and [crampons]".

As the group faced a few unexpected challenges – including a curious case of missing equipment – Skog explains that the prospect of turning around did enter her mind, but she was still drawn to the peak. "[I thought] we should turn around, because this is crazy. But again... we are looking up and we can see the summit there. We are so close," Skog says. "The closer you get to the summit, the harder it is to turn around."

"It is like a kind of compulsion, an inexorable force pulling them further and further up the mountain," Petrzela says.

In what would later be known as the 2008 K2 disaster – coming after a similar 1986 tragedy that saw five people die on the mountain – a massive ice avalanche swept away climbers' rope lines, causing many to fall from an especially treacherous section of the mountain known as the "Bottlekneck". The incident killed 11 climbers, including Bae. Even the ones lucky enough to make it off K2 were dealing with frostbite and other injuries. Survivors, Petrzela explains, felt "shellshocked, like a soldier returning from war."

The names of the climbers were added to the makeshift memorial at basecamp. Reports would call the incident "one of the worst tragedies in Himalayan history".

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Still, Skog continued adventuring – partly, she says, to feel the same sense of wonder she shared with her husband. She enlisted friends to trek across Greenland and, later, she completed an unassisted crossing of Antarctica. She has even returned to the Himalayas, though her new perspective has shifted everything, even summit fever.

"I did not have the same feeling being there. I felt that this does not belong to me anymore," she says.

*This article is adapted from a script by Natalia Mehlman Petrzela and Leigh Meyer.

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