The gigantic Patagonian Ice Sheet covered southern Chile in a thick blanket of ice and snow during the last Ice Age. Around 12,000 years ago, rising temperatures caused it to begin melting, carving out the Patagonian landscape as it receded. Today, two vast sections, northern and southern, remain of this ancient ice sheet. Together, they cover more than 5,400 square miles and form the third largest frozen landmass on Earth. At their edges are towering glaciers of blue-tinged ice, whose ever-changing faces create the large icebergs that float in the fjords and channels.