“Pyrenees La Nuit” aims to improve the quality of cross-bordering ecosystems by protecting and enhancing a very specific aspect: natural nighttime darkness. The increase of light pollution means a loss for this natural value, which is in fact, a decisive environmental factor for the state of biodiversity, ecosystems, and human health. The final and key result of this project is the development of a Pyrenean Strategy for the protection and improvement of the nocturnal milieu quality, which may serve as a reference and a roadmap for other enclaves or areas wanting to address the same issue. For this purpose, actions of different types will be carried out: measurements, studies, development of analytical tools, dissemination and mediation activities, congresses, international certification processes for Dark Sky reserves, or the publication of guides of best practices. The project foresees also the adaptation of some facilities that will serve as centers of operation for the different actions. The partnership is formed by 6 entities, which will develop the project's actions in different emblematic sites in the Pyrenees: Sierra de Montsec, Pic du Midi, Bagnères de Bigorre, Roncal Valley and Pamplona. The development and implementation of the project will be made in a joint and cross-bordering way. This approach will allow, among other things, to actualize and position the Pyrenees as an international reference in this field.