Fitz Roy / Laguna de los Tres

Laguna de los Tres is the glacial tarn directly beneath Cerro Fitz Roy, the 3,405 m granite spire that dominates the skyline of Los Glaciares National Park in Argentine Patagonia. Named for the three first ascensionists of Fitz Roy in 1952, the lake is the climax of Patagonia's most famous day hike — a 24 km out-and-back from the trailhead town of El Chaltén that has become the unofficial postcard view of the Argentine south.

The route starts on flat ground at the edge of El Chaltén, climbing a steep first kilometre to the Mirador Río de las Vueltas, then easing into rolling lenga forest along a wide-open valley with the Fitz Roy massif always ahead. Past Campamento Capri the trail flattens through wetlands and the Río Blanco to Campamento Poincenot — a free park-service campground used by climbers heading to the towers. From Poincenot the final kilometre to the lake is brutal: a 400 m climb up a steep scree slope on rough switchbacks that take an hour to ascend. The reward at the top is the lake, the granite cirque, and the towers — Fitz Roy centre, Aguja Poincenot and the spires of the Cerro Torre group either side. The descent is the same path back to town.

The walking season is November to April. Outside that window the upper switchbacks are snowbound and dangerous. There's no permit, no fee, and no guide required — El Chaltén is essentially a hiking village with the trailhead at the end of its main street. Most hikers do the whole 24 km in a single long day (8–10 hours including the lake stop); fitter walkers run it. Many also stay overnight at Campamento Poincenot to be at the laguna for sunrise, when the towers turn briefly blood-orange — though this only works if the famously fickle Patagonian weather plays along. Wind is the constant — exposed sections near the top can be impossible in a gale, and Mountain Rescue Argentina advises turning back rather than crowning the climb on a bad day.