In my profession as a miniature landscape designer or terrain builder I am very interested in all kinds of inspiration. One kind of inspiration is the real world. Pictures of small areas like a sand formation or erosion on beaches caused by tide for example.
Here you can explore how processes work that are building landscape. For example the erosion of wind on sand which is comparable to sandstone in some areas. Or the way how streams of water do model a sandy and muddy soil.
There are a lot of examples to find and I will keep on searching.