OMG You don't know what sand dunes are!
In physical geography, a dune is a hill of sand built by eolian processes. Dunes are subject to different forms and sizes based on their interaction with the wind. The "valley" or trough between dunes is called a slack. A "dune field" is an area covered by extensive sand dunes. Large dune fields are known as ergs.
Some areas have one or more sets of dunes running parallel to the shoreline directly inland from the beach. In most such cases the dunes are important in protecting the land against potential ravages by storm waves from the sea. Although the most widely distributed dunes are those associated with coastal regions, the largest complexes of dunes are found inland in dry regions and associated with ancient lake or sea beds.
Dunes also form under the action of water flow (alluvial processes), on sand or gravel beds of rivers, estuaries and the sea-bed.
The word 'dune' derives from a medieval Germanic or Norse word - "dun", a hill.
thanks to wiki. My definition would be hills made of sand, Well i did ecology so i know alot about the but they're kick ass