A generation ago Ethiopia's Tigray province was stricken by a famine that shocked the world. Today, as Chris Haslam reports, local people are using ancient techniques to turn part of the desert green.
In the pink-streaked twilight, a river of humanity is flowing across Tigray's dusty Hawzien plain. This cracked and desiccated landscape, in Ethiopia's far north, occupies a dark corner of the global collective memory. Thirty years ago, not far from here, the BBC's Michael Buerk first alerted us to a biblical famine he described as "the closest thing to hell on earth".