There is no mistaking Observation Hill when you arrive at McMurdo, if you know anything about it. It is a distinct cone, right at the end of the peninsula – even if you've never seen a picture of it, its name alone tells you it's a prime lookout: sticking out into McMurdo sound as it does, it has clear views in every direction.

I had seen pictures of it, but I was still surprised how it loomed over the station. Unlike the vastly larger Mt Erebus, it is visible from everywhere; whether you're eating in the Galley or crawling back to bed from the Crary lab in the wee hours, it's always looking over your shoulder.

Though not apparent in the above photo, it is clearly visible in person that there is a large cross mounted nearly at the peak of the hill. Visitors especially from the States might assume it is just another expression of religious devotion – Christ died on a cross on a hill, so hilltop crosses are not unusual in a country which puts great stock in expressions of Christianity – but this is not another one of those things, in fact it isn't even American. This cross was erected in January 1913 by the surviving men of the Terra Nova Expedition, as a memorial to Captain Scott and the other members of his party who died out on the Ross Ice Shelf on their way home from the South Pole.

Before the ship arrived it was decided among us to urge the erection of a cross on Observation Hill to the memory of the Polar Party. On the arrival of the ship the carpenter immediately set to work to make a great cross of jarrah wood [an Australian hardwood]. There was some discussion as to the inscription, it being urged that there should be some quotation from the Bible because "the women think a lot of these things." But I was glad to see the concluding line of Tennyson's "Ulysses" adopted: "To strive, to seek, to find, and not to yield."

... Observation Hill was clearly the place for it, it knew them all so well. Three of them were Discovery men who lived three years under its shadow: they had seen it time after time as they came back from hard journeys on the Barrier: Observation Hill and Castle Rock were the two which had always welcomed them in. It commanded McMurdo Sound on one side, where they had lived: and the Barrier on the other, where they had died. No more fitting pedestal, a pedestal which in itself is nearly 1000 feet high, could have been found.

(Apsley Cherry-Garrard, The Worst Journey in the World, pp.565-7)

The establishment of the cross took two days: the first, to hack a hole in the volcanic rock in which to mount it, and the second to carry up the pieces and erect them.

It stands nine feet out of the rocks, and many feet into the ground, and I do not believe it will ever move. When it was up, facing out over the Barrier, we gave three cheers and one more. (ibid., p.567)

106 years later, there is a hiking trail up Observation Hill. I had intended to make a pilgrimage since the moment I arrived, but with everything else going on, and the ongoing challenge to get enough sleep, it wasn't until quite late in my visit that I finally made it.

My first attempt was on a relatively fine day, when I thought I could get some good views. The trailhead was clearly marked on the station map, but when I got there I couldn't find a way to reach it without crossing a fuel pipeline, and I had a dim recollection from orientation that this was a big no-no. I wandered about looking for access until I started getting a headache from the fumes, and gave up.

The next opportunity came a few days later, after I'd found out from a veteran that it was OK just to step over the pipeline there. It was a thickly cloudy day, and hazy by Antarctic standards, so I wouldn't get as good a view, but that did mean I could look forward to having the hill to myself. So I stepped over the pipeline and started up.

It looks like a terribly steep climb from the bottom, but once on the slope it's not so bad, and is far less slippery than the gravel slope of Arrival Heights. Partway up I passed a mountain rescue class, but beyond that the trail was entirely mine.

Like the rest of Ross Island, Observation Hill is volcanic in origin – in fact it was once a small volcano of its own. Unlike the subglacial volcano that is now Castle Rock, which grew cylindrically through a hole it melted in the ice, Observation Hill must have been uncovered in its later years at least, because it has the classic cone shape made by molten rock running down the outside. It is a lighter colour than much of the rest of the exposed rock in the area, and in places, it gives a really good impression of being sedimentary rather than igneous.

While the climb was not as physically intense as I had feared, it did still make me very warm, and I had two pauses, not to catch my breath but to cool down. One was to watch the rescue class, the other was when, somewhere near the top, I lost the trail, and examined the terrain for a while to guess which side would be least fall-off-able. I chose the wrong one, it turns out – I didn't fall off, but I did have to pick my way over some bare rock and came out above the cross, which is mounted in a pocket of rubble just off the peak.

It's hard to tell from the photo but it is in fact quite large – I am an average sized female and I stood well under the crossbar. The inscription is still there, but over a century of blizzards have battered it, and some parts are just barely decipherable.

The names – above of the worst of the blowing grit – are still legible. This gave me one of those moments which always seems to come by surprise. I have lived most of my life, and certainly all of my career, in close proximity with fictional characters, who demand to be believed in, either out of escapist necessity or professional duty. Most of the time I am off in my own little world, and the fact that that little world is now a historical moment in Antarctica does not, necessarily, make it more real, in relation to my literal present reality, than any movie I've worked on. I know these guys were real, I’ve seen film footage of them, and read their handwriting, and even met members of their families! But when I'm up to my elbows in the work, it's easy to give them the part of my brain that suspends disbelief on a production. Suddenly something will come along that jolts me back to their reality: in this case, a name carved on a physical object by someone who knew them personally.

At the same time, this physical object impressed upon me again just how much time separates their reality and mine. Originally the cross was painted white, with the incised letters filled in black. Only a little of the white paint remains in the deepest recesses of what are quite shallow letters, now. In 1960, when Silas Wright returned and was photographed up here, the wood had already been scoured clean. His visit was 47 years after the cross was put in place, and 49 years before mine. The same imagination that conflates historical realities with fictional ones can make those years evaporate, but that is still a lot of years, and erosion, unlike imagination, doesn't lie.

Cherry may have believed that the cross would never move, but it has in fact blown down twice, once in the winter of 1974 and again in 1993. Its restoration in 1994 was a significant effort: a new concrete "boot" was made for it at Scott Base and delivered to the site by helicopter, and the cross itself was relayed up the hill by teams of helpers. (You can see photos of the event here, p.44) I cannot say how moving it is to see such an outlay of resources and enthusiasm by people who never met the Polar Party, to perpetuate their memory.

The cross isn't the only thing to see at the top of Observation Hill, of course – there is everything else. It turned out to be the perfect way to end my tour of Terra Nova landmarks, not only because it was the last bit of home territory the Terra Nova men themselves visited, but because I could see nearly everywhere I'd been from up here.

There was McMurdo Station itself, which I had come to know and love over the last month …

Cape Evans, and the science huts up on Arrival Heights …

The whole of the Castle Rock hiking trail …

Cape MacKay, on the other side of which is Cape Crozier …

The airfields, too small to be seen in this picture, though those with sensitive vision may make out the smudge of Williams Field at left …

And some melt pools in the pressure at the base of the hill, which had not factored in my travels at all but were very attractive and glowed in the diffuse light.

As you can see, it was not the greatest day for landscape photography, what with the matte light and the taller mountains being covered with cloud. But I had not come up here to take pictures. The sombre atmosphere befitted what I had come to do, which was to remember these men and thank The Powers That Be for the blessings that had been showered upon me in the last few weeks.

The cross faces south, towards their last camp, and the Pole. This is, of course, a thoughtful and fitting aspect of the memorial. It also gives the impression of a beacon, a light in a window, a lighthouse on a headland, guiding them home. The men who erected it knew their friends were dead. They are still dead. We all know this. But they are still out there somewhere, and it is not impossible to imagine some small irrational part of the human psyche wanting, in some small way, to show them the way back, and call them home by name.

Minna Bluff was covered in cloud, so I couldn't use it as a bellwether, but the wind started to pick up and was colder than before, so I thought I should start heading down again. The correct trail was obvious from this end, and I poked along it for a little way before everything caught up with me and I sat down to have a little cry.

The cross is a historical artefact, and while it is not as plum or as complex as the huts, it still requires conservation. Alarmed by the degree of erosion on the lettering, the Antarctic Heritage Trust has devised a shell to protect it from the worst of the winter winds. That will do something, but it has already lost a lot. When I was up there, I wondered why it hadn't ever been repainted, as the paint would go a long way to protecting it, and when the paint wore off it could just get repainted instead of eating further and further into the wood. The raw timber is more harmonious with the environment, and I like it better aesthetically that way, as do many others I'm sure – the white cross with black letters in Debenham's photo from 1913 is very stark and artificial in such a magnificent landscape. But it would last a lot longer.

On the other hand, generations of Antarcticans now have the cross as a touchstone, not only as their link to the history (not everyone gets to visit Cape Evans) but as a landmark in their own experience of Antarctica. It was personally important to the men who painted it white and put it up, but it is also personally important to hundreds, if not thousands, of people since then, who have never seen it white and don't know that's how it started, and might see the repainting as a travesty. If it were to be conserved, to what extent would that go? Would the letters be re-carved deeper, obliterating what remains of Davies' original work? At what point does conservation end and adulteration begin?

The alternative is to take down the original and keep it somewhere out of the weather – Scott Base perhaps – and replace it with a replica. Jarrah is still available, the letters could be carved afresh, it could be the bare wood everyone has known and loved for the last fifty years at least, and the original could be saved from the effects of weather once and for all. But doesn't this defeat the intent of the original in some way, and make it – dare I say – a Disneyland version? Do we owe more to history to keep it as it is and let the elements wear it down, or to preserve it as long as possible and do whatever might be necessary to extend the experience and historical understanding of a place, if not its authenticity?

These are all questions that curators and conservators have been grappling with for years, so I leave it to them to make the decisions. I am grateful to have seen the original, and to have a moment to myself up there to reflect on these things, and more. I hope, whatever happens with it in the future, Observation Hill is not de-crossed entirely. How else will they find the way home?

Sarah Airriess – Blog