Lago Posadas

Lagos Posadas and Pueyrredón lie end to end in a valley of western Santa Cruz, separated by a low bar of gravel a few hundred metres wide, and the striking thing is that the two waters are quite different colours: Posadas a deep green-blue, Pueyrredón a milky turquoise fed by glacial melt from the Andes to the west. Red sandstone cliffs and eroded formations rise around them, including the arch known as the Arco de Piedra, and the surrounding country holds rock art, guanacos, condors and flamingos on the shallows. The village of Lago Posadas is tiny. Pueyrredón continues across the border into Chile, where it is called Cochrane, and the mountains beyond hold Cerro San Lorenzo.

What you actually see

• The two-coloured lakes - contrasting waters divided by a gravel bar.
• The red cliffs - sandstone walls and eroded shapes around the valley.
• The stone arch - the Arco de Piedra formation near the lakes.
• The wildlife - guanacos, condors and flamingos in an empty landscape.

When to go

November to March, when the gravel roads are most reliable; the area is exposed and hard to reach in winter. Wind is severe here even by Patagonian standards and can make walking difficult through the afternoon.

Honest expectations

This is deep in the empty part of the RN40 corridor: fuel, food and accommodation are minimal and should be arranged in advance. Roads are gravel and washboarded. There is no phone signal over much of the area.

Nearby

Bajo Caracoles is the fuel stop on the RN40; Cueva de las Manos lies south along the same route.