Viewed from space, the western edge of the Sahara Desert looks like another world. Its abundance of red-tinged sand turns into a sea of dunes that ebb and flow with the wind, unabated by foliage ...

I got my first lesson in the physics of sand dunes in 1998 on an expedition ... Nor did I realize the allure of dunes. Once I started flying in the desert, I came under its spell and began what ...