http://cdn3.spiegel.de/images/image-667872-galleryV9-hmcv.jpg
The Namib Desert on the west coast of Africa is one of the world's oldest. It has existed for around 80 million years. This satellite image shows the Tsauchab River, which only flows immediately following heavy rainfall, only to disappear again almost immediately. Despite appearances, this image is of the dry river bed. The white markings are salt deposits. The line running horizontally across the bottom third of the photo is a road connecting two settlements. The Namib is virtually uninhabited save for a handful of settlements and indigenous groups.

http://www.spiegel.de/international/a-957494.html