Star dunes - sometimes called pyramid dunes - stand out among sand dunes for their towering height and eye-catching form.

Sossusvlei is part of the Namib Desert, which is considered the world's oldest desert, dating back at least 55 million years.

This story appears in the November 2012 issue of National Geographic magazine. I got my first lesson in the physics of sand dunes in 1998 on an expedition into the Sahara. In order to take aerial ...