The Etosha pan is a large endorheic salt pan, forming part of the Kalahari Basin in the north of Namibia. The 120-kilometre-long (75-mile-long) dry lakebed and its surroundings are protected as Etosha National Park, one of Namibia's largest wildlife parks. The pan is mostly dry but after a heavy rain it will acquire a thin layer of water, which is heavily salted by the mineral deposits on the surface of the pan, which most of the year is dry mud coated with salt.
It is assumed that the Kunene River fed the lake at that time, but tectonic plate movements over time caused a change in river direction, resulting in the lake running dry and leaving a salt pan. Now the Ekuma River is the sole source of water for the lake. Typically, little river water or sediment reaches the dry lake because water seeps into the riverbed along its 250-kilometre (160 mi) course, reducing discharge along the way.
The surrounding area is dense mopane woodland which is occupied by herds of elephants on the south side of the lake. Mopane trees are common throughout south-central Africa, and host the mopane worm, which is the larval form of the moth Gonimbrasia belina, and an important source of protein for rural communities. The salt desert supports very little plant life except for the blue-green algae that gives the Etosha its characteristic colouring, and grasses like Sporobolus spicatus which quickly grow in the wet mud following a rain. Away from the lake there is grassland that supports grazing animals.