The driest place on Earth are certain areas of Antarctica, especially the polar plateau, which receives little to no precipitation, and when it does occur, only in the form of fine ice crystals and no more than a few cm a year. The driest place in Antarctica known (lacking an ice cover) are the McMurdo Dry Valleys, which, due to strong gusts of dense wind, are very sparse in surface moisture. If an animal such as a seal dies here, it becomes mummified for decades, as there is very little native life to decompose it. The McMurdo Dry Valleys are being extensively studied by scientists, who compare the climate to that of Mars.
Another driest place is the Atacama desert in Chile, some parts of which have received absolutely zero precipitation in centuries. Parts of the Atacama desert may actually exceed the dryness of most of Antarctica, though data from the latter is insufficient to tell. The Atacama desert is so dry that mountains of height 6,885 m (22,590 ft) have no glaciers, making them unique in the world. Studies have shown that the Atacama desert received no appreciable rainfall between 1570 and 1971, and some ancient riverbeds appear to have been dry for 120,000 years. Like the McMurdo Dry Valleys, parts of the Atacama desert have been compared to Mars, and have actually been used to film extraterrestrial scenes in science fiction movies.
The driest place of all in the Atacama desert is the high coastal crest-line, which receives no marine fog whatsoever. The entire desert is created by a "rain shadow" caused by the Andes mountains to the west, which absorb all moisture before it can reach the area. In 1569, Alonso de Ercilla, a Spanish soldier, wrote "Towards Atacama, near the deserted coast, you will see a land without men, where there is not a bird, nor a beast, nor a tree, nor any vegetation." The driest place in the desert is so devoid of life that no microbes whatsoever can be detected in the soil.