the streaks in this photos are streams of sand powered by the winds which flow in from the ocean, pushing the little grains unto the dunes, growing them over time, creating beautiful sculptures on one hand, and on the other hand killing any vegetation on its path. thats the ugly side of sand dunes - they are a seductive but destructive force of desertification. i read somewhere that some of the sands which land in these dunes travel all the way from north africa...