Whether was always the Sahara Desert?

Whether was always the Sahara Desert?
The Sahara Desert located on the African continent is considered the biggest desert in the world. Its area makes more than 7 mln sq.km. Whether always it was so?

It appears, no! Researchers say that long a time ago the climate of Sahara differed from the modern radically. It was subtropical, very damp landscape with magnificent vegetation. Here the deep rivers flew – scientists found their dried-up courses. Now here only also drive sand. Though in some places this sand very surprising - "singing". The remains of a former landscape can be met only in violently blossoming oases. Scientists call number - 2700 years ago – Sahara finally turned into the desert. This process was long and irreversible. Researchers base conclusions on results of analyses of the geological deposits taken from a lake Yoa bottom in the Central part of the desert.

In Sahara the interesting desert phenomenon – mirages is observed. Researchers of mirages counted to 160 thousand mirages annually. There are even cards of places where they are observed regularly and now it is tourist routes. Maybe mirages show the past of Sahara – mountain chains, the raging rivers, palm groves, rainforests.
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