A long trek across the desert of northeastern Niger brings the visitor to one of the most astonishing and rewarding sights in the Sahel: fortified villages of salt and clay perched on rocks with the Saharan sands laying siege below. Generations of travellers have stood before the “ksars” of Djado, wondering at their crenelated walls, watchtowers, secretive passages and wells, all of them testifying to a skilled but unknown hand. Who chose to build this outpost in a scorched and desolate region — and why they built it — are questions that have never been fully answered. And just as beguiling is why it was abandoned. No archaeological dig or scientific dating has ever been undertaken to explain the mysteries. Djado lies in the Kawar oasis region 1,300 kilometres (800 miles) from the capital Niamey, near Niger’s deeply troubled border with Libya. Once a crossroads for caravans trading across the Sahara, Kawar today is a nexus for drug and arms trafficking. Its grim reputation deters all but the most determined traveller. “There have been no foreign tourists since 2002”, said Sidi Aba Laouel, the mayor of Chirfa, the commune where the Djado sites are located. “When tourism was good, there was economic potential for the community.” A blessing of sorts occurred in 2014, when gold was discovered. It saw an influx of miners from across West Africa, bringing life and some economic respite, but also bandits who hole up in the mountains. Few of the newcomers seem interested to visit the ksars.