Dune is a hill or ridge made of sand. Dunes are shaped and moved by the wind over time. They can be small or very large and may change shape as the wind shifts the sand. Some dunes form long lines, while others appear as isolated hills.

Dunes are found in deserts and coastal areas around the world. They form over time as sand is carried and deposited by wind. Dunes are part of sandy ecosystems and support plants and animals adapted to these environments.