What is Dune?
[[File:Mesquite Sand Dunes - Death Valley California (50233228801).jpg|thumb|Mesquite Sand Dunes - Death Valley California]] In [[physical geography]], a '''dune''' is a [[hill]] or ridge of [[sand]], usually [[Deposition (geology)|deposited]] by [[eolian processes]] (wind) or sometimes by the flow of water. Dune fields cover large parts of some [[desert]]s, and some [[beach]]es have dunes. [[Mars]] has many dunes. Sand dunes have different forms and sizes based on their interaction with the [[wind]]. Sometimes they migrate downwind. {{River morphology|state=collapsed}} {{-}} {{geo-stub}} [[Category:Landforms]]