Orange Dunes of the Namib Desert, Namibia – July 18th, 200924.7S 15.2E
Stretching 1,200 miles in length, but averaging a width of only 70 miles, the Namib Desert is home to the highest sand dunes in the world. Here, the crests of the red and orange dunes of the Namib dune sea create long lines parallel to the coast.
In physical geography, a dune is a hill of sand built by aeolian processes. Dunes are subject to different forms and sizes based on their interaction with the wind. Most kinds of dune are longer on the windward side where the sand is pushed up the dune, and a shorter “slip face” in the lee of the wind. The “valley” or trough between dunes is called a slack.
Some coastal areas have one or more sets of dunes running parallel to the shoreline directly inland from the beach. In most cases the dunes are important in protecting the land against potential ravages by storm waves from the sea. Although the most widely distributed dunes are those associated with coastal regions, the largest complexes of dunes are found inland in dry regions and associated with ancient lake or sea beds.