The mountain sectors of southwestern Europe are experiencing a critical situation of depopulation and ageing, which makes it essential to revitalise their social and productive structure. This project faces this challenge through the development of the internal potential of five pilot cases, which seeks to value the heritage associated with their cultural landscapes as a tool for social innovation that offers new development opportunities to mountain communities, improving their quality of life, territorial cohesion and the development of new economic resources. This will help mitigate the significant territorial, social and economic imbalances that exist today. In recent decades, archaeological research carried out in mountainous regions of southwestern Europe has shown that these are not only natural and biodiversity areas, but also contain an important cultural legacy resulting from the intense human activity that has shaped these cultural landscapes over time. However, this cultural background characteristic of mountain areas is little known and has been underestimated as a tool for the dynamisation, innovation and sustainable transformation of these territories. It is proposed to enhance the cultural landscapes of mountains and their heritage to offer new opportunities for development to local communities. This will improve their quality of life, strengthen territorial cohesion and diversify services and employment options in the territory, promoting the self-esteem of the local population and increasing the capacities of public bodies to attract visitors, integrate new population and fix young people to their territories. The creation of an international cooperative network linked to mountain cultural landscapes is a milestone for the development of joint strategies between Spain, Portugal and France to enhance and exploit cultural heritage as a resource for sustainable territorial development.