No rivers or mountains for today, but dunes. A lot of dunes. The image of the day is a satellite image from the Arabic peninsula. What you can see are a thousand of so called barchan dunes. Barchan dunes form when there is a limited amount of sand available and one major wind direction. We all can imagine a classic desert, such as the Sahara, with endless seas of sand dunes, very similar to a rough sea. It is build from an infinite sand pool which seems to have no bottom. This is different in the way that the sand layer is shallow and underneath there is a harder flat plane. Sadly, the exact reason why exceeds my knowledge but I still wanted to show you this amazing pattern built by the wind!