Antarctica - is the driest place on Earth. Some areas of this continent have not seen rain for two million years.
Technically, the desert is the place where the annual rainfall of less than 254 mm of rainfall.
In the Sahara, for example, drops of only 25 mm. The average annual precipitation in Antarctica is about the same, but 2% of the continent, known as the Dry Valleys, completely free of ice and snow, and there never is rain.
Next on dry place on Earth - the Atacama Desert in Chile. In some areas it rains has been observed for 400 years, and the average annual rainfall is the tiny figure of 0, 1 mm. Such paltry figures do Atacama second dry desert of the world - 250 times the land of the Sahara.
However, Antarctica is not only the driest place on the planet. At the same time the mainland claims the title of the wet and very windy. It was there, in the form of ice, is 70% of world reserves of water and winds reach speeds of beating all world records.
The unique natural conditions in the area of the Dry Valleys are caused by so-called katabatic winds (from the Greek word meaning "blowing down"). They occur when cold, dense air descends the hill only by gravity. Such winds can reach speeds of 320 km / h, fully evaporating moisture along the way - water, ice, snow.
Although Antarctica in terms of definitions, is desert, the driest part of it, somewhat ironically, called oases. They are so close to the natural conditions of Mars that NASA spends test reentry spacecraft "Viking».