Bahía Lapataia
Ruta 3 ends here, at the terminus of one of the longest continuous road routes on Earth. The sign at the road's end reads: Fin de la Ruta Nac. No. 3 — Ushuaia 12 km — Alaska 17.848 km. The bay takes its name from the Yaghan word for "bay of the forest," and the name fits: the surrounding sub-Antarctic beech forest reaches almost to the water's edge, broken by boardwalks that thread through peat bog and beaver-flooded meadow. North American beavers were introduced to the island by the Argentine navy in 1946 — fifty pairs, intended to seed a fur trade that never materialised — and they have since transformed enormous stretches of the park's riparian habitat, felling lenga beech and creating flooded clearings that are still ecologically controversial. The evidence is everywhere near Lapataia: skeletal trunks standing in still water, wide dams of pale chewed timber, and the occasional beaver itself if you are patient and quiet near the Castorera trail.
From Bahía Lapataia, Puerto Arias is a short walk along the boardwalk, offering a broader vantage over the bay from a slightly elevated position on the eastern shore. The bay itself is sheltered from the prevailing westerlies, which is why the Yaghan used it as a recurring campsite — the same quality of shelter that makes it a pleasant place to sit for a while now.