Answer:
In countries with desertic and/or coastal ecosystems. For example, Australia, Peru, Namibia, the United States of America, China.
Explanation:
Dunes are incredible hills of loose sand that are created by the flow of the wind and its deposition. They are formed near a desert or a coastal area and their size depends on the amount of sand that has accumulated over time.
Dunes exist in many parts of the world, from America and Europe to Asia and Australia. However, according to research sources, the following regions exhibit the most striking dunes: