The Rub' al-Khali desert The Rub al-Khali desert is the longest stretch of desert in the world. © Sylvain Saustier
The Rub' al-Khali, meaning the Empty Quarter, occupies almost half the country, and spills into the Sultanate of Oman and the United Arab Emirates. This is the largest sandy desert in the world, but unfortunately there is no possibility of taking expeditions there. This is a shame, as in certain places you can really talk about canyons of sand dunes, with some dunes taller than the Eiffel Tower. You can also see impressive impacts from meteorites there, lost in the middle of the desert.