Hippos once wallowed in lakes in the middle of Arabia's Empty Quarter
Arabia's Empty Quarter is one of the driest places on Earth, with dunes reaching 250 metres. Yet hardened lake beds along its middle hold fossils of hippopotamus, water buffalo and long-horned cattle, relics of brief wet spells when monsoon-like downpours filled shallow basins thousands of years ago.
The Rub' al Khali stretches about 1,000 kilometres long and 500 wide across the southern third of the Arabian Peninsula, spilling across Yemen, Oman, the Emirates and Saudi Arabia. The ground sinks from about 800 metres in the southwest to near sea level in the northeast. Feldspar tints the sand reddish-orange, and yearly rain usually totals under 50 millimetres. Oddly, the dunes barely move; wind strips sand from their surfaces, but moisture seeping up from salt flats seems to anchor their bases.
The ancient lakes formed twice, between 6,000 and 5,000 years ago and again between 3,000 and 2,000 years ago. Most lasted only a few years, though some fed by runoff from the Tuwaiq Escarpment survived for up to 800. Snails, tiny crustaceans and freshwater clams lived in them, and chipped flint tools show people visited, though no human remains have turned up. Frankincense caravans crossed stretches that are now almost impassable until around 300 AD, and satellite images reveal camel tracks invisible on the ground.
Life persists. Scorpions, rodents and the prized black camels of Oman live here, while the western reserve of 'Uruq Bani Ma'arid shelters sand gazelles, Rüppell's foxes and Saudi Arabia's only wild Arabian oryx, reintroduced between 1995 and 2013. It became the kingdom's first natural World Heritage site in 2023. Beneath the sand lie riches too: the giant Ghawar field reaches into the desert's northern edge.
Outsiders first documented crossings in the early 1930s, when Bertram Thomas and St John Philby made their journeys, and Wilfred Thesiger later mapped much of it, as told in Arabian Sands. Recent decades have brought a run of firsts: Hajar Ali became the first woman known to cross it in 2012, and in 2025 two Britons dragged every supply in homemade carts for 22 days without resupply.
Source: Rub' al Khali
