One of the world’s largest dune fields, the Great Sand Sea straddles Egypt and Libya, stretching more than 800km from its northern edge near the Mediterranean coast south to Gilf Kebir. Covering a colossal 72,000 sq km, it contains some of the largest recorded dunes in the world, including one that is 140km long. It was off limits to foreigners at the time of writing.
Crescent, seif (sword) and barchan dunes are found here in abundance, and have challenged desert travellers and explorers for hundreds of years. The Persian king Cambyses is thought to have lost an army here, while the WWII British Long Range Desert Group spent months trying to find a way through the impenetrable sands to launch surprise attacks on the German army. Aerial surveys and expeditions have helped the charting of this vast expanse, but it remains one of the least-explored areas on the planet.