This is a shot along the length of the Etosha Pan, a 135km / 75 mi long flat salt pan in Namibia's Etosha National Park. It has a touch of a green cast from the mineral salts on its surface and while this picture was taken during dry conditions, during the rainy season it is covered by a thin layer of water.
It's one of the few places in the world that I've been where you can see the horizon while looking over dry land. The B&W treatment brings out the texture of the salt pan surface and it almost looks like water. The dark splashes on the ground are shadows cast by the clouds. The dark in the distance is the bottom of the clouds.