At the southern end of the Andes, where the mountains give way to the Patagonian steppe and the wind arrives without warning from the west, the granite towers of Torres del Paine rise above glacial lakes of an improbable blue that has nothing to do with sky and everything to do with rock flour suspended in meltwater. The W Trek takes four to five days and passes through some of the most concentrated dramatic scenery available on foot anywhere on earth: the Grey Glacier calving into its lake, the French Valley amphitheatre of hanging ice and rock, the base of the towers themselves at dawn when the light turns them briefly orange. The guanacos are indifferent to all of this and wander across the trails at their own unhurried pace. The weather changes every twenty minutes and that is simply part of the agreement.

