A desert is a special natural area that is primarily characterised by very low humidity, as well as very modest plant and animal life.
A common belief is that deserts are hot, but this is not invariably true. Those deserts located near the equator could have a temperature of 60° C. However, even Antarctica has a desert: the famous McMurdo Dry Valleys. Annual precipitation in deserts does not exceed 200 mm, but in some places it is reduced to 1 mm. The relief of all deserts is flat, though small uplands do occur.
Deserts are classified according to the type of their soil. Sandy deserts are, as it is difficult to guess, filled with sand. Sahara (the largest desert in the world), the Arabian Peninsula and the Karakum Desert belong to this type.
In stony deserts the soil is hard and tough, and no plant can grow on it. The Ovaihi (USA) and Tanami (Australia) deserts are stony.
Some deserts are covered with clay, thus they are called clay deserts. There are no isolated clay deserts in the world, but there are stony-clay deserts: Kalahari (Africa) and Negev (Israel).
The surface of solonchak deserts is covered with salts. They are often formed in the place of dried-up lakes. Typical representatives of this type are the Desht-Lug (Iran) and the Great Salt Lake Desert (USA).
So-called snow deserts belong to a separate category – they are located in the territory of the Arctic and Antarctica. They are classified as deserts due to their modest flora and fauna, rather than a lack of precipitation.
It is not the Sahara that is ranked as the driest desert in the world, but the Atacama, located in Chile. The temperature does not rise above 30°C, however the Atacama receives a maximum of 50 mm of rainfall per year, due to wind and current patterns. No significant rainfall has been recorded here in more than 4 centuries of tracking.