Now it's just a matter of ascending the staircase that climbs up among rocky outcrops and flora, which includes what looks like hebes almost undistinguishable from ones found at home. Cape Horn is a national park and a World Biosphere Reserve so each of the landmarks on top of the island is linked by a board walk to protect the unique flora and fauna.
Perched at the top is a dramatic, tall metal sculpture dedicated to those who have perished trying to round the horn. Cape Horn. It was erected by the Chilean Brotherhood of Captains of Cape Horn (the international brotherhood includes New Zealanders). It is designed to create the silhouette of an albatross (several species of which have often accompanied our ship over the previous two days). From the base of the sculpture we can see what, in strict geographic terms, is the true southernmost point of South America, which is on an almost inaccessible headland nearby.
Cape Horn is officially the southernmost headland on the Tierra del Fuego group of islands rather than the actual southernmost point of South America but to most people that's splitting hairs. We are 55 degrees 59 minutes south and only the Drake Passage of about 800km of open water separates us from Antarctica.
Of course this is no ordinary stretch of ocean - this is the realm not of the roaring forties but the furious fifties and the screaming sixties that blow almost continuously from west to east, (Sailing the other direction is not advised - in 1905 the ship Susanna took 99 days to "Round the Horn".
Seas are routinely mountainous and rogue waves, created by the combination of hundreds of kilometres of unbroken ocean suddenly meeting the relatively shallow seas off the cape and the landmass itself, can tower 30 metres above vessels.
Rounding the cape has always been a treacherous business and today is almost entirely the realm of recreational sailors. Since the Drake Passage was first sailed in 1616 (its namesake Frances Drake had been blown of course to the tip of Tierra del Fuego in 1578 but hadn't navigated the passage or identified Cape Horn at the time).
Since that time, the Cape has struck fear and foreboding into many a mariner's heart, as well as becoming an irresistible challenge to many. "Rounding the Horn" is regarded as the Everest of sailing.
Charles Darwin, in whose wake we have been sailing for the past few days, saw the Cape in 1834 and wrote: "One sight of such a coast is enough to make a landsman dream for a week about shipwrecks, peril and death."
There have been over 800 vessels wrecked in these waters with 10,000 people sent to a watery grave. That's one reason why the Chilean Navy maintains a presence on the island. They have a lighthouse here (there's another at the true Cape), which is manned by a naval officer who lives here with his wife, son and German Shepherd dog.
The crew tell us we're lucky to have struck such a "good" day. The sky is a swirling mass of thick clouds, the wind on top of the cape is biting and icy skiffs of rain sting our cheeks. The seven-metre-high albatross monument to those lost at sea is magnificent and is made even more poignant by the poem by Sara Vial that is alongside:
"I am the albatross that awaits you at the end of the world ... I am the forgotten soul of the sailors lost, rounding Cape Horn from all the seas of the world. But die they did not in the fierce waves, for today towards eternity in my wings they soar in the last crevice of the Antarctic winds."
A walkway suspended over the lichens, mosses and cushion-like low vegetation that clothe the cape leads us past the small wooden Stella chapel and into the lighthouse keeper's cottage, which has been enfolded into the lighthouse itself (presumably a safety measure given the often extremes of weather). The family in residence are waiting inside with a full range of End of the World and Cape Horn merchandise. I'm impressed with their enterprise, after all custom must be erratic to say the least.
We're starting to get the hurry-up from the crew. The weather maybe on the change and they want us back on the ship before the sea conditions become too dangerous for the zodiacs. There's time for one last look south, into the churning waves and where albatross are soaring. According to myth, albatrosses are the souls of drowned mariners - down here at the end of the world one could well believe it's true.
Jill Worrall cruised in Patagonia with assistance from Cruceros Australis.