So in the oasis of intelligentsia that is TED, I stand here before you this evening as an expert in dragging heavy stuff around cold places. I've been leading polar expeditions for most of my adult life, and last month, my teammate Tarka L'Herpiniere and I finished the most ambitious expedition I've ever attempted. In fact, it feels like I've been transported straight here from four months in the middle of nowhere, mostly grunting and swearing, straight to the TED stage. So you can imagine that's a transition that hasn't been entirely seamless. One of the interesting side effects seems to be that my short-term memory is entirely shot. So I've had to write some notes to avoid too much grunting and swearing in the next 17 minutes. This is the first talk I've given about this expedition, and while we weren't sequencing genomes or building space telescopes, this is a story about giving everything we had to achieve something that hadn't been done before. So I hope in that you might find some food for thought.

It was a journey, an expedition in Antarctica, the coldest, windiest, driest and highest altitude continent on Earth. It's a fascinating place. It's a huge place. It's twice the size of Australia, a continent that is the same size as China and India put together.

As an aside, I have experienced an interesting phenomenon in the last few days, something that I expect Chris Hadfield may get at TED in a few years' time, conversations that go something like this: "Oh, Antarctica. Awesome. My husband and I did Antarctica with Lindblad for our anniversary." Or, "Oh cool, did you go there for the marathon?" (Laughter)

Our journey was, in fact, 69 marathons back to back in 105 days, an 1,800-mile round trip on foot from the coast of Antarctica to the South Pole and back again. In the process, we broke the record for the longest human-powered polar journey in history by more than 400 miles. (Applause) For those of you from the Bay Area, it was the same as walking from here to San Francisco, then turning around and walking back again. So as camping trips go, it was a long one, and one I've seen summarized most succinctly here on the hallowed pages of Business Insider Malaysia. ["Two Explorers Just Completed A Polar Expedition That Killed Everyone The Last Time It Was Attempted"]

Chris Hadfield talked so eloquently about fear and about the odds of success, and indeed the odds of survival. Of the nine people in history that had attempted this journey before us, none had made it to the pole and back, and five had died in the process.

This is Captain Robert Falcon Scott. He led the last team to attempt this expedition. Scott and his rival Sir Ernest Shackleton, over the space of a decade, both led expeditions battling to become the first to reach the South Pole, to chart and map the interior of Antarctica, a place we knew less about, at the time, than the surface of the moon, because we could see the moon through telescopes. Antarctica was, for the most part, a century ago, uncharted.

Some of you may know the story. Scott's last expedition, the Terra Nova Expedition in 1910, started as a giant siege-style approach. He had a big team using ponies, using dogs, using petrol-driven tractors, dropping multiple, pre-positioned depots of food and fuel through which Scott's final team of five would travel to the Pole, where they would turn around and ski back to the coast again on foot. Scott and his final team of five arrived at the South Pole in January 1912 to find they had been beaten to it by a Norwegian team led by Roald Amundsen, who rode on dogsled. Scott's team ended up on foot. And for more than a century this journey has remained unfinished. Scott's team of five died on the return journey. And for the last decade, I've been asking myself why that is. How come this has remained the high-water mark? Scott's team covered 1,600 miles on foot. No one's come close to that ever since. So this is the high-water mark of human endurance, human endeavor, human athletic achievement in arguably the harshest climate on Earth. It was as if the marathon record has remained unbroken since 1912. And of course some strange and predictable combination of curiosity, stubbornness, and probably hubris led me to thinking I might be the man to try to finish the job.

Unlike Scott's expedition, there were just two of us, and we set off from the coast of Antarctica in October last year, dragging everything ourselves, a process Scott called "man-hauling." When I say it was like walking from here to San Francisco and back, I actually mean it was like dragging something that weighs a shade more than the heaviest ever NFL player. Our sledges weighed 200 kilos, or 440 pounds each at the start, the same weights that the weakest of Scott's ponies pulled. Early on, we averaged 0.5 miles per hour. Perhaps the reason no one had attempted this journey until now, in more than a century, was that no one had been quite stupid enough to try. And while I can't claim we were exploring in the genuine Edwardian sense of the word — we weren't naming any mountains or mapping any uncharted valleys — I think we were stepping into uncharted territory in a human sense. Certainly, if in the future we learn there is an area of the human brain that lights up when one curses oneself, I won't be at all surprised.

You've heard that the average American spends 90 percent of their time indoors. We didn't go indoors for nearly four months. We didn't see a sunset either. It was 24-hour daylight. Living conditions were quite spartan. I changed my underwear three times in 105 days and Tarka and I shared 30 square feet on the canvas. Though we did have some technology that Scott could never have imagined. And we blogged live every evening from the tent via a laptop and a custom-made satellite transmitter, all of which were solar-powered: we had a flexible photovoltaic panel over the tent. And the writing was important to me. As a kid, I was inspired by the literature of adventure and exploration, and I think we've all seen here this week the importance and the power of storytelling.

So we had some 21st-century gear, but the reality is that the challenges that Scott faced were the same that we faced: those of the weather and of what Scott called glide, the amount of friction between the sledges and the snow. The lowest wind chill we experienced was in the -70s, and we had zero visibility, what's called white-out, for much of our journey. We traveled up and down one of the largest and most dangerous glaciers in the world, the Beardmore glacier. It's 110 miles long; most of its surface is what's called blue ice. You can see it's a beautiful, shimmering steel-hard blue surface covered with thousands and thousands of crevasses, these deep cracks in the glacial ice up to 200 feet deep. Planes can't land here, so we were at the most risk, technically, when we had the slimmest chance of being rescued.

We got to the South Pole after 61 days on foot, with one day off for bad weather, and I'm sad to say, it was something of an anticlimax. There's a permanent American base, the Amundsen-Scott South Pole Station at the South Pole. They have an airstrip, they have a canteen, they have hot showers, they have a post office, a tourist shop, a basketball court that doubles as a movie theater. So it's a bit different these days, and there are also acres of junk. I think it's a marvelous thing that humans can exist 365 days of the year with hamburgers and hot showers and movie theaters, but it does seem to produce a lot of empty cardboard boxes. You can see on the left of this photograph, several square acres of junk waiting to be flown out from the South Pole. But there is also a pole at the South Pole, and we got there on foot, unassisted, unsupported, by the hardest route, 900 miles in record time, dragging more weight than anyone in history. And if we'd stopped there and flown home, which would have been the eminently sensible thing to do, then my talk would end here and it would end something like this.

If you have the right team around you, the right tools, the right technology, and if you have enough self-belief and enough determination, then anything is possible.

But then we turned around, and this is where things get interesting. High on the Antarctic plateau, over 10,000 feet, it's very windy, very cold, very dry, we were exhausted. We'd covered 35 marathons, we were only halfway, and we had a safety net, of course, of ski planes and satellite phones and live, 24-hour tracking beacons that didn't exist for Scott, but in hindsight, rather than making our lives easier, the safety net actually allowed us to cut things very fine indeed, to sail very close to our absolute limits as human beings. And it is an exquisite form of torture to exhaust yourself to the point of starvation day after day while dragging a sledge full of food.

For years, I'd been writing glib lines in sponsorship proposals about pushing the limits of human endurance, but in reality, that was a very frightening place to be indeed. We had, before we'd got to the Pole, two weeks of almost permanent headwind, which slowed us down. As a result, we'd had several days of eating half rations. We had a finite amount of food in the sledges to make this journey, so we were trying to string that out by reducing our intake to half the calories we should have been eating. As a result, we both became increasingly hypoglycemic — we had low blood sugar levels day after day — and increasingly susceptible to the extreme cold. Tarka took this photo of me one evening after I'd nearly passed out with hypothermia. We both had repeated bouts of hypothermia, something I hadn't experienced before, and it was very humbling indeed. As much as you might like to think, as I do, that you're the kind of person who doesn't quit, that you'll go down swinging, hypothermia doesn't leave you much choice. You become utterly incapacitated. It's like being a drunk toddler. You become pathetic. I remember just wanting to lie down and quit. It was a peculiar, peculiar feeling, and a real surprise to me to be debilitated to that degree.

And then we ran out of food completely, 46 miles short of the first of the depots that we'd laid on our outward journey. We'd laid 10 depots of food, literally burying food and fuel, for our return journey — the fuel was for a cooker so you could melt snow to get water — and I was forced to make the decision to call for a resupply flight, a ski plane carrying eight days of food to tide us over that gap. They took 12 hours to reach us from the other side of Antarctica.

Calling for that plane was one of the toughest decisions of my life. And I sound like a bit of a fraud standing here now with a sort of belly. I've put on 30 pounds in the last three weeks. Being that hungry has left an interesting mental scar, which is that I've been hoovering up every hotel buffet that I can find. (Laughter) But we were genuinely quite hungry, and in quite a bad way. I don't regret calling for that plane for a second, because I'm still standing here alive, with all digits intact, telling this story. But getting external assistance like that was never part of the plan, and it's something my ego is still struggling with. This was the biggest dream I've ever had, and it was so nearly perfect.

On the way back down to the coast, our crampons — they're the spikes on our boots that we have for traveling over this blue ice on the glacier — broke on the top of the Beardmore. We still had 100 miles to go downhill on very slippery rock-hard blue ice. They needed repairing almost every hour. To give you an idea of scale, this is looking down towards the mouth of the Beardmore Glacier. You could fit the entirety of Manhattan in the gap on the horizon. That's 20 miles between Mount Hope and Mount Kiffin. I've never felt as small as I did in Antarctica. When we got down to the mouth of the glacier, we found fresh snow had obscured the dozens of deep crevasses. One of Shackleton's men described crossing this sort of terrain as like walking over the glass roof of a railway station. We fell through more times than I can remember, usually just putting a ski or a boot through the snow. Occasionally we went in all the way up to our armpits, but thankfully never deeper than that.

And less than five weeks ago, after 105 days, we crossed this oddly inauspicious finish line, the coast of Ross Island on the New Zealand side of Antarctica. You can see the ice in the foreground and the sort of rubbly rock behind that. Behind us lay an unbroken ski trail of nearly 1,800 miles. We'd made the longest ever polar journey on foot, something I'd been dreaming of doing for a decade.

And looking back, I still stand by all the things I've been saying for years about the importance of goals and determination and self-belief, but I'll also admit that I hadn't given much thought to what happens when you reach the all-consuming goal that you've dedicated most of your adult life to, and the reality is that I'm still figuring that bit out. As I said, there are very few superficial signs that I've been away. I've put on 30 pounds. I've got some very faint, probably covered in makeup now, frostbite scars. I've got one on my nose, one on each cheek, from where the goggles are, but inside I am a very different person indeed. If I'm honest, Antarctica challenged me and humbled me so deeply that I'm not sure I'll ever be able to put it into words. I'm still struggling to piece together my thoughts. That I'm standing here telling this story is proof that we all can accomplish great things, through ambition, through passion, through sheer stubbornness, by refusing to quit, that if you dream something hard enough, as Sting said, it does indeed come to pass. But I'm also standing here saying, you know what, that cliche about the journey being more important than the destination? There's something in that. The closer I got to my finish line, that rubbly, rocky coast of Ross Island, the more I started to realize that the biggest lesson that this very long, very hard walk might be teaching me is that happiness is not a finish line, that for us humans, the perfection that so many of us seem to dream of might not ever be truly attainable, and that if we can't feel content here, today, now, on our journeys amidst the mess and the striving that we all inhabit, the open loops, the half-finished to-do lists, the could-do-better-next-times, then we might never feel it.

A lot of people have asked me, what next? Right now, I am very happy just recovering and in front of hotel buffets. But as Bob Hope put it, I feel very humble, but I think I have the strength of character to fight it. (Laughter)

Thank you.