To locals, the high mountain peaks are more than just breathtaking natural phenomena. Known as achachilas in Aymara and apus in Quechua, they’re also considered living beings inhabited by powerful spirits. As controllers of weather and the source of vital irrigation water, these mountain gods must be appeased with constant offerings and worship, since if angered they’re liable to send hailstorms, frost or drought to destroy crops. At almost every high pass you’ll see stone cairns known as apachetas. As well as marking the pass on the horizon to make it easier for travellers to find, these apachetas are also shrines to the mountain gods. Travellers carry stones up to the pass to add to the apacheta, thereby securing the good will of the achachilas and leaving the burden of their worries behind. Offerings of coca and alcohol are also made at these shrines, which vary in size and form from jumbled heaps of rocks to neatly built piles topped by a cross, depending on the importance of the route and the relative power and visibility of the nearby peaks.