The key issue addressed in this chapter is the capacity of outstanding heritage sites to serve as a local resource and to drive a territorial development dynamic. Indeed, territories that have remarkable heritage sites are both highly specific (due to the presence of that attraction) and subject to significant regulatory frameworks, including the mandatory protection of their sites. Ruault and Talandier use a mixed methodology approach: quantitative (socio-economic, fiscal and environmental variables to create typologies and evaluate site impacts) for all the sites, and qualitative (survey of local managers and field research) for targeted study sites. The results show that heritage sites can boost the local economy. However, this is not always the case: their positive impact on local jobs, attractiveness and income differs according to the local context. Indeed, a remarkable heritage site entails multiple development constraints but also has huge potential for leveraging cooperation and greater profits usable for site protection. Thus, the findings question the concept of a territorial resource: its mere presence does not ensure local development, and it is necessary to rethink its role as part of a more dynamic model to extend it to the medium to long term so as to accommodate successive interactions between the asset and development. Ultimately, the aim is to turn the territory into a resource for heritage sites and vice versa by striking a balance that benefits both.