Where Am I?

CLUES

1. This area covers more than 3 million hectares.
2. Wind, along with river and ocean currents, carried materials thousands of kilometers to form these desert dunes.
3. The area includes gravel plains, coastal flats, rocky hills, a coastal lagoon and ephemeral rivers.
4. Fog is the primary source of water here and provides an enviroment for insects, reptiles and mammals.

ANSWER  Namib Sand Sea, Namibia