Road interrupted by a sand dune, Nile Valley, Egypt. Dunes cover nearly one-third of the Sahara, and the highest, in linear form, can attain a height of almost 1,000 feet (300 m). Barchans are mobile, crescent-shaped dunes that move in the direction of the prevailing wind at rates as high as 33 feet (10 m) per year, sometimes even covering infrastructures such as this road in the Nile Valley. [map] (© Yann Arthus-Bertrand)
No comments:
Post a Comment