Marie Byrd Land contains the largest volcanic region in Antarctica, covering a length of almost along the Pacific coast. The volcanism is the result of rifting along the vast West Antarctic Rift System, which extends from the base of the Antarctic Peninsula to the surrounding area of Ross Island, and the volcanoes are found along the northern edge of the rift. Protruding up through the ice are a large number of major shield volcanoes, including Mount Sidley, which is the highest volcano in Antarctica. Although a number of the volcanoes are relatively young and are potentially active (Mount Berlin, Mount Takahe, Mount Waesche, and Mount Siple), others such as Mount Andrus and Mount Hampton are over 10 million years old yet maintain uneroded constructional forms. The desert-like surroundings of the Antarctic interior, along with a very thick and stable ice sheet which encloses and protects the bases of the volcanoes, which decreases the speed of erosion by an issue of perhaps a thousand relative to volcanoes in moist temperate or tropical climates.