Imagine a sea of sand dunes the size of a European country, a world in motion, exquisite ridge lines perfectly sculpted by the winds and stretching to a layered horizon. Or a remote mountain massif in black rock or sandstone, hewn by the elements and marked in red ochre with the passage of ancient rock artists. Or a salt pan shimmering to a seemingly endless horizon. Welcome to the world's deserts, a realm of astonishing and dramatic beauty, as much places of the soul and the imagination as actual physical terrain.