What a seal bodyguard and 2,200-year-old moss have to do with a watershed moment in exploration history.

On April 24, 1916, just four years shy of one hundred years ago, five men led by polar explorer Ernest Shackleton, the third officer on Captain Scott’s Discovery Expedition, set out on an 870-nautical-mile journey on a 22-foot glorified rowboat across the Drake Passage. Shackleton and his crew were marooned on Elephant Island after losing their ship to the Weddell Sea.

They were coming to their own rescue.

I, too, was headed to South Georgia; it was the same trip, though certainly not the same journey. I looked out the windows of the National Geographic Explorer, secure and comfortable, as we rounded the far eastern point of Elephant Island. I saw the cove where Shackleton and his men found some small respite from the icy waters, and drew a mental picture of that place, too depleted after my morning’s efforts to even go get my camera.

Two days later we were in South Georgia, a veritable paradise of animals, vegetation, and exposed geology, like the story of the world writ large on the landscape itself. And here, too, are etched the final chapters of the Shackleton story; the thumbnail of a beach where they first landed, the spot they set out overland across terrain just this side of passable, a hike over a last ridge that separated an impossible journey of perseverance back into a remote outpost of civilization: a whaling station in Stromness Bay.

The captain pulled us so far into Stromness Harbor we were practically on the beach. Despite some cloud cover and a bit of snow coming in, our conditions were calm that day, and I hopped into a Zodiac with Stephanie Martin, a marine mammal researcher, and we zipped back out into the bay and down one harbor to Husvik. The moss I was now after, my “back up moss,” if you will, is 2,200 years old, and growing on top of a 9,000-year-old fossil bed. Fortified with the research and a map provided from Nathalie Van der Putten who discovered this bank, I once again scanned the outline of the topography to home in on Kanin Point.

The beach and tussock grass was so lousy with seals that Stephanie became my de facto seal bodyguard, and likewise instructed me on how to keep them at bay. The first rule is to make loud noises. The second was to carry a paddle from the Zodiac. One might be tempted to smack a snarling male fur seal on the head, but it isn’t necessary — just tapping them on the flippers is deterrent enough. (Which is not to say that no one got bitten over the course of this expedition.)

I climbed through the tussock and saw the ancient mounds of peat. I had found it. I took some photos, this time close in, feeling unbelievably fortunate to have found not just one, but both of these ancient moss banks — the needles in a polar haystack.

Later the same afternoon, I hiked overland from a protected inlet into the plot where Shackleton is buried. My heart was once again clutched with the grip of this place, ancient and primeval in its makeup. It was akin to a wide-eyed first visit to the surface of another planet.

If Shackleton’s story had been written as fiction, surely someone would criticize it for having an unrealistic number of obstacles. He had returned to South Georgia five years after his harrowing circuit, and, as if living on borrowed time, died of a massive heart attack the very night he arrived. He died having no idea he shared Elephant Island with one of the oldest living things on the planet, nor that he would end his journey in South Georgia just a stone’s throw from yet another. But I have a feeling he would have approved of the quiet perseverance of these unassuming mosses, in this landscape that speaks of deep time, the power of the natural world, and the precariousness of life in its clutches.

I poured some whiskey on Shackleton’s grave, and some for me, too.