The Cordillera Occidental is the westernmost arm of the Andes — a line of dormant and active volcanoes that forms the natural western border of the Altiplano. From a distance, many of its peaks are perfectly conical, their symmetrical shapes rising above the high plateau like landmarks placed by design. The terrain here is severe and beautiful in equal measure: thin air, volcanic rock, and a colour palette that runs from black lava fields to the white of salt flats.