Since 2007, the Great Green Wall project, led by the African Union, aims to fight against the spread of the desert by restoring natural ecosystems within a 15 km wide and 7,800 km long strip that crosses eleven Sahelian countries. Originally conceived as a vegetal barrier to hold the desert back, the project now has a broader approach: sustainable management and restoration of these arid ecosystems. Fifteen years after its launch, how is the Great Green Wall evolving? What challenges does it face and what are its future prospects? Discover the project through five questions.