The Sossusvlei area belongs to a wider region of southern Namib with homogeneous features (about 32.000 km²) extending between rivers Koichab and Kuiseb. This area is characterized by high sand dunes of vivid pink-to-orange color, an indication of a high concentration of iron in the sand and consequent oxidation processes. The oldest dunes are those of a more intense reddish color. These dunes are among the highest in the world; many of them are above 200 metres, the highest being the one nicknamed Big Daddy, about 325 metres high, however the highest dune in the Namib Desert, Dune 7,
