Show sahara immensity Imm entity in amilca are natural wonders i which almost challenge belief the sahara a vast waste of rock gravel and sand la Is so 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 direction down from the dry heart of central asia Asla instead of from the moisture giving ocean the temperature changes so sharply at nightfall that travelers who have suffered in the blazing heat beat find themselves shivering under bli pLeta this immense area of desolation served as a ta highly effective shield which long protected central africa from overland exploration from the north gilbert grosvenor in the nat lional geographic Magaz magazine lne i |