Isla Grande de Tierra del Fuego is the heart of the archipelago - 48,000 square kilometers of mountain, forest, and steppe split between two countries. The border runs roughly north-south, giving Argentina the eastern triangle and Chile the western wilderness. Most of the island's population lives on the Argentine side: Ushuaia at the bottom, facing the Beagle Channel, and Río Grande in the north, an oil and fishing town that few tourists visit.

The landscape shifts dramatically as you cross the island. The Argentine side opens into rolling steppe, not unlike Patagonia to the north - wind-bent grass, estancias with their sheep, big skies. But approach the mountains and everything changes: sub-Antarctic forest closes in, peaks rise sharp and snow-covered, and the air takes on that particular wet cold that seeps through every layer. Ruta 3, Argentina's southernmost highway, ends here, its Mile Zero marker a popular photo opportunity for those who've driven from Buenos Aires.

The Yámana, the Selk'nam, the Kawésqar - the indigenous peoples of Tierra del Fuego lived in one of the harshest environments on Earth. The Yámana paddled bark canoes through the channels, diving for shellfish in water barely above freezing. The Selk'nam hunted guanaco across the steppe. They survived for millennia without metal tools, without agriculture, without permanent shelter.

Then came the Europeans. Missionaries arrived to save souls; ranchers arrived to raise sheep. The land the Selk'nam had hunted became enclosed pasture. Bounties were placed on indigenous heads. Disease did what violence left incomplete. By 1920, the Selk'nam were effectively extinct. One elderly Yámana speaker reportedly survives today, living in Chile. The fires that gave Tierra del Fuego its name have long gone out.

The waterway that separates the main island from the maze of smaller islands to the south bears the name of Darwin's ship, which surveyed these waters in the 1830s. Captain FitzRoy charted the coast; Darwin observed, collected, and began forming the ideas that would become the theory of evolution. The channel remains a working waterway - cruise ships, naval vessels, fishing boats all pass through, watched by sea lions on rocky islets and cormorants on the cliffs.

Boat tours from Ushuaia cruise the channel past penguin colonies and the iconic Les Eclaireurs lighthouse, often incorrectly called 'the lighthouse at the end of the world' (the real one is on Isla de los Estados). The mountains rise directly from the water on both shores. Glaciers tongue down from peaks that receive snow year-round. The border with Chile runs down the middle of the channel, invisible but meaningful - two countries sharing one of Earth's most dramatic seascapes.

South of the main island, the archipelago dissolves into a chaos of smaller islands, channels, and exposed rock, culminating in Cabo de Hornos - Cape Horn. For centuries, this was the only route between the Atlantic and Pacific oceans, a passage dreaded by every sailor who attempted it. The winds are relentless, the seas enormous, the cold brutal. Ships foundered here in their hundreds; thousands of sailors drowned.

Today, Cape Horn National Park protects the southernmost piece of land before Antarctica - Isla Hornos, a steep-sided rock where an albatross sculpture commemorates the dead and a Chilean naval family maintains the lighthouse. Expedition cruises visit in calm weather, landing passengers who can claim they've stood at the uttermost south. The Drake Passage stretches beyond, 1,000 kilometers of the roughest ocean on Earth before the ice begins.

Tierra del Fuego's modern life centers on Ushuaia - a city of over 80,000 that has grown from prison colony to tourist hub to gateway for Antarctic expeditions. The old prison is now a museum. The Beagle Channel fills with cruise ships. Ski resorts operate on the slopes above town, among the southernmost in the world. The tax-free zone Argentina established to encourage settlement has created an unlikely electronics industry; factories assemble phones and televisions at the end of the Earth.

But the wilderness remains, pressing in from all sides. Tierra del Fuego National Park protects ancient forest and peat bog at the edge of the channel. The Chilean side is emptier still - Porvenir a small town, the rest largely uninhabited, accessible only by ferry or small plane. And always, everywhere, the wind - the same wind that scattered the sparks of those ancient Yámana fires, the wind that will be here long after the last tourist departs.