Four and a half thousand square kilometres of Antarctica with no ice on it. Katabatic winds, cold dense air pouring downhill under gravity, scour the valleys so hard that snow evaporates within hours in summer, and the Transantarctic Mountains put the whole area in a snow shadow; a century of records averages about 100 mm of precipitation a year, essentially all of it snow that does not stay. The surrounding mountains also block the ice sheet from flowing in. It is the largest ice-free region on the continent and still only 0.03 percent of it. NASA has treated the valleys as the closest thing on Earth to the surface of Mars since the Viking programme in the 1970s, and tests hardware here for that reason. Victoria Land, west of McMurdo Sound.
Victoria Land, Antarctica
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