For most people, the word “desert” conjures a simple image of an endless, sandy, rippled landscape. Reality is vastly more variegated. About a third of Earth’s land surface, in fact, is defined as desert through the simple calculation of a precipitation deficit. But the biggest portion of that desiccated area has no sand in sight: It’s the interior of Antarctica. Only a fifth of the world’s desert area is sandy. Even in sandy regions, variations in wind patterns can create an array of astonishingly strange vistas. Here, particularly strange dot-shaped dunes on the plain of Wādī Ḩazar in Yemen’s portion of the Rubʿ al-Khali, or Empty Quarter, on the Arabian Peninsula.