|The rock towers of the Torres del Paine are some of the most famous and difficult summits in the world, not climbed until the 1950s. The summits are protected from climbers by the technical difficulty of the rock and Patagonia's severe weather. They are situated in Chile on the the edge of the Hielo Sur (the Patagonian Ice Cap). This is the third largest ice field in the world after Antarctica and the Greenland Ice Cap. The ice cap and the mountain ranges on its edge are surrounded by the south American pampas (enormous grassy plains). The sun heats up the pampas during the day and the warm air on the plains rises up into the atmosphere, to be replaced by the heavier cold air which flows down off the ice cap. This movement generates the incredible winds which tear around the Torres constantly.