The 14-hectare Fort site inhabits the meeting point between several distinct landscapes and topographies, its rich architectural and natural heritage creating a wide variety of environments. The fort is located by the northern edge of the Plateau de Saclay, perched in the hills above the municipality of Buc and overlooking the Bièvre Valley. The site is part of the regional landscape that our firm knows well, joining a growing list of area projects including the Plateau de Saclay, the Versailles Pion, and the Étangs Gobert. Built in 1879 and later abandoned in the 1990s, a thick native forest has regrown throughout the space, the multitude of species cultivating a lush hub of biodiversity in need of preservation. The ruderal woodland is thoughtfully sculpted, shaping a dialogue of open and dense spaces. Resulting clearings are linked using paths surfaced with lightweight aggregate or slats. In other areas, existing plant cover is bolstered. Acer, Corylus, and Tilia plants expand existing species composition, while Fraxinus and Salix plants are added in areas more prone to wetland conditions. The Fort moats, an important feature of the site’s architectural heritage, are revived and transformed into a promenade open to the public. The resulting kilometer-long, landscaped promenade is a celebration of the fort’s architectural heritage. A manicured lawn stretching before the structure highlights existing archways. Habitat-specific management practices are put in place throughout this rich mix of environments.