The red iron in the dunes is emphasised at sunrise by the low angle of the rising sun. The dunes are either side of the dry Tsauchab River. An occasional tree dots the river flats. Stretching 1,600 kilometres (1,000 miles) in length, but averaging a width of only 110 kilometres (70 miles), the Namib Desert is home to the highest sand dunes in the world up to 340 metres high. Namib Naukluft National Park, at Sussovlei, Namibia, Africa.