Digital 3D Technologies for Preserving and Transmitting Cultural heritage and Historical Memories

In an era marked by both environmental transformations and the resurgence of conflicts, the preservation of cultural and historical memory faces unprecedented challenges. Whether submerged by dam reservoirs or obscured by the passage of time, landscapes and cultural heritages risk fading from collective memory. Yet, these elements are crucial for educating current and future generations about the impacts of human activity or conflict on local populations. This communication explores how 3D digital technologies, particularly 3D Geographic Information Systems (GIS) and geovisualization, can restore these threatened memories and make them accessible to a broad audience. Using two case studies, we will demonstrate the potential of these tools to reconstruct, archive, and disseminate lost or endangered heritage.First, we will examine the Gorges de la Loire valley in France, where the construction of reservoir dams submerged landscapes and cultural sites . By combining 3D GIS with historical databases, we created a "backup copy" of the flooded valley, enabling local populations to re-appropriate their submerged heritage. This approach not only preserves the memory of lost landscapes but also provides a model for safeguarding other sites threatened by environmental changes.Second, we turn to Saint-Étienne during World War II, where events and local community memories risk being forgotten . Here, 3D GIS and virtual reality tools were used to archive and visualize the city’s wartime experiences, from resistance, occupation and collaboration acts to bombed neighborhoods.By integrating maps, 3D models, and immersive videos, we developed a multidimensional archive that engages diverse audiences – from researchers to students and local inhabitants – in exploring the past.Our methodology highlights three key contributions:1.Technological Innovation: The use of 3D GIS and geovisualization to create dynamic, interactive representations of lost or threatened heritage.2.Cultural Preservation: The development of digital archives that serve as memory backups.3.Public Engagement: The adaptation of these tools for educational and commemorative purposes, fostering a deeper understanding of historical and environmental impacts.