Researchers Uncover ‘Secrets’ of African Sand Dune

Researchers used radar and other technologies to study a large “star” sand dune in eastern Morocco. The oldest parts of the base of the dune are estimated to be about 13,000 years old.

Source : https://learningenglish.voanews.com/a/researchers-uncover-secrets-of-african-sand-dune/7515043.html