The territory of the Phlegraean Fields, where the geography of a volcanic crater landscape intertwines with widespread archaeological remains, embodies a complex cultural identity shaped by the continuous interaction between natural processes and human intervention. Seismic and bradyseismic phenomena, together with centuries of settlement, extraction, and construction, have produced a stratified landscape in which mythology, geology, and architecture coexist. Within this context, the article reflects on the role of architecture as a tool for interpreting and preserving cultural identity, assuming archaeology—both classical and industrial—as an infrastructure of the landscape. After outlining the historical and cultural framework of the Phlegraean Fields, the contribution focuses on the Gulf of Baia as a case study, analysing the transformation from a “landscape of ruins” to a “ruined landscape”, and subsequently to a “rediscovered landscape”. The research is verified through a design study on the Aragonese Castle of Baia and the adjacent Lubrano pozzolana quarry, where the architectural project operates as a connective device capable of integrating visible and hidden traces of history. By reconfiguring former defensive structures and industrial voids into a new system of accessibility and public spaces, the project demonstrates how architecture can reconnect fragmented landscapes, reinterpret archaeological heritage, and restore continuity between the fortress, the city, and the sea.