Show Sa sahara haras immensity in africa are natural wonders which almost challenge belief the sahara a vast waste of rock gravel and sand Is so bis big it would hold the entire continental united states the reason it Is a desert at all Is simply stated that the wind blows in the wrong direct direction lon down from the dry heart of central asia instead of from the moisture giving ocean the temperature changes so sharply at nightfall that travelers who have suffered buffered in the blazing heat find themselves shivering under blankets this immense area of desolation served as a highly effective shield which long protected central africa from overland exploration from the north gilbert grosvenor in the national geographic magazine |