The project site is Capo d’Orso military fortress, located in the north corner of Sardinia. It was built on the top of a craggy mountain in the 19th century. The military function, its support premises, and the walls of the fortress form an organic unit. On the disorganized fortress massing, the most distinctive elements are the stairs, various spaces stitched to the fortress wall and the massing embedded into the ground. Playing with these elements we have integrated the new massing in a present-day and delicate fashion, which satisfy the museum function. In the original concept at the lower parts of the complex, next to the entrance, the ‘L’ shaped building poses as a negative corner, disconnected from the main path as an individual element. The existing gate cannot function as a main entrance for a public facility. Our plan makes a motion to deal with these two problems. The connection of the ‘L’ shaped building to the fortress’ transport route, new entrance and access situation have been renewed. By choosing the common cross section of the massing, after elongating and abstracting, a new rectangular space structure arose. We put the entrance area where these cross sections meet by curling out the bordering walls. From the open space encompassed by the new walls, we arrive through a lavish stair to the ‘L’ shaped building which contains an indoor museum, an archive and a library. From the open space and entrance area, a visitor centre can be reached where tourist information is available, and conferences and gatherings can be held. By fully unfolding the glass walls the inner space unites with the entrance area. The whole fortress, the existing buildings and sites, gestures hold a historic value, and all are the part of the exhibition by their own right. The road to the citadel on the top of the mountain leads between retainer walls. These retainer walls have two levels, so it can be reached both from the fortress and the road. The military memorial was placed here. As the trench widens, the visitor can rest here and focus on the exquisite panorama. The design puts the stair in the focal point which dissolves the slit and lodging the structure to the ground creates a connection with the surroundings. To the additions we chose a neutral material, a subtly layered concrete, which reacts gently to the surroundings but fortifies the contemporary gesture at the same time.