Through an approach at different levels of intervention – from urban design to constructive detail – Prof. Emmanuel Rey's studio aims at analyzing and exploring with the specific issues related to the contribution of the architectural project to the transition of urban areas. Entitled HELVEPOLIS, the 2026-2027 studio will investigate territories shaped by the rise of fossil fuels, exploring opportunities to rethink strategic sites to foster a more ecological relationship with the territory, such as the site near Nyon railway station.Developed as a prospective approach to the low-carbon transformation of the urbanized areas of the Swiss Plateau, Helvepolis transcends the divide between city and countryside. It is based on the vision of a structured ensemble of diverse territories whose components operate in synergy and are interconnected through spatial, cultural, landscape, and infrastructural networks. Since the Industrial Revolution, this territory has been profoundly shaped by the rise of fossil fuels and transformed by the development of energy and transport infrastructures. This carbon-intensive era has had major environmental, climatic, and spatial impacts. While these legacies can sometimes be difficult to embrace, they also offer opportunities to rethink strategic sites and foster a more ecological relationship with the territory. Beyond abstract large-scale visions, architectural projects can propose, at their own scale of intervention, concrete catalysts for urban transition and climate adaptation.Located in the immediate vicinity of Nyon railway station, the site selected for the 2026–2027 studio is emblematic of these challenges. Currently occupied by a large asphalt parking area along the railway tracks and a few residential buildings with little interaction with the public realm, it is characterized both by its fragmentation and its privileged location. These conditions invite architectural reflection on its potential to accommodate new residents and jobs, and on the possibility of creating an ecological, bioclimatic neighbourhood shaped by a new form of urbanity.Positioned between utopia and realism, this decidedly forward-looking approach envisions the comprehensive urban regeneration of a place already profoundly shaped by human intervention. In programmatic terms, the HELVEPOLIS studio is based on a mix of housing and activities, with particular attention paid to the quality of living in an urban environment. The approach also includes a careful consideration of landscape strategies and the network of public spaces in relation to the site’s specific characteristics.