In a context of climate crisis and dwindling resources, this course explores how architecture and land use planning can actively contribute to the ecological transition. Adopting an ecological approach involves rethinking our ways of designing space, integrating new climatic, material, and social constraints into the heart of the project. We will cover the foundations of the bioclimatic approach, the history of passive comfort techniques, and current levers for reducing the ecological footprint of projects and developing a regenerative approach. Particular attention will be paid to bio-sourced, geo-sourced, and reused materials, as well as the notion of metabolism as a new framework for architectural and urban thinking.