The Danakil Depression in northern Ethiopia is one of the lowest, hottest places on the surface of the Earth.
Yet every year thousands of traders from the Ethiopian Highlands make the arduous and exhausting journey into this vast super-heated bowl, their long camel trains tied nose-to-tail with rough rope.
And what draws them into this desolate, alien landscape is salt.
Blocks of it are cut from the ground, loaded onto the camels and transported using methods unchanged for at least 2000 years.
Matthew Parris joins the traders and their camels to follow the ancient salt route from the Danakil Desert to the Ethiopian Highlands.