Soils are the foundation of our terrestrial ecosystems and soil health is crucial to global food production. In this short video interview with Marc-André Selosse, botanist and mycologist, professor at the National Museum of Natural History in Paris, let's discover this complex underground ecosystem on which we depend to feed ourselves. We will discover why soil health is a fundamental principle of agroecology, what are the threats to soil health in Europe and what are the levers of change to improve soil health in Europe and worldwide. The video interview has been realised within the framework of the first edition of the Month of Agroecology with the financial support from the LIFE Program of the European Union, the Fondation de France and the Fondation Ecotone.