Liwa is where Abu Dhabi began. The Bani Yas were farming dates in this hundred-kilometre crescent of oases by the 16th century, and in 1761 one of their hunting parties found fresh water on a coastal island; that island grew into Abu Dhabi city, and in 1793 the ruling Al Nahyan family moved down from these sands to the coast. The oases line the northern rim of the Rub' al Khali — the Empty Quarter, the largest continuous sand desert on Earth. Beyond the last palm gardens the dune sea takes over: quartz grains stained rust-red by a film of iron oxide, heaped into long parallel ridges by the shamal, the northwesterly wind that blows down the Gulf. The best known of them is Moreeb Dune, Tal Moreeb — Arabic for "terrifying" — which runs 1.6 kilometres long and falls away at more than 50 degrees, a wall of sand steep enough that drivers come from across the Gulf to find out whether an engine can climb it.
The desert is best met at the edges of the day, when low sun rakes the ripples and the sand turns copper and violet. Winter mornings can bring something stranger: fog settles into the hollows between the dunes and leaves only the red crests showing above it. People come to bash across the sand in 4x4s, board down Moreeb's face, ride camels along the ridgelines and camp where the only sound is wind moving grain. A paved road now runs to the foot of the dune, so reaching it takes no 4x4 at all. From mid-December to early January the Liwa International Festival brings hill climbs, drag racing and heritage camps to its base; in mid-July, when the heat is punishing and the visitors gone, the oases hold their own festival for the date harvest.