Argentina's Ushuaia may be famous as the southernmost city on Earth, but it's tiny, tiny Puerto Williams, Chile, on Isla Navarino, that can lay claim to being the southernmost settled community on the planet. An overnight in the wind-whipped fishing community is a highlight, but the rugged surroundings are the real draw.
From Puerto Williams, hearty hikers with navigation experience can head out on the Dientes Circuit, an unmarked track that circumnavigates the island. (A good map and working compass are musts.) There are no established campsites—this is roughing it—but the views across the water of the other mountainous islands of Tierra del Fuego are incredible.
The Dientes track was developed in the late '90's, but only in recent years has it started to gain real traction, as the number of trekkers in other Patagonian regions continue to grow and those seeking solitude are driven elsewhere. Now, travelers more comfortable with support can enlist one of a half-dozen or so outfits offering trips of the Dientes. Erratic Rock is one of the best guiding companies in the region.