Can sand dunes be 800 feet tall and stretch for miles?

Yes, sand dunes can reach heights of 800 feet and stretch for miles. The tallest sand dunes are typically found in deserts or coastal areas, where wind patterns and the availability of sand allow for their formation. An example is the height of the Duna Grande in the Namib Desert, which is around 1,066 feet tall. These large dunes can create stunning landscapes and unique ecosystems.