From the old city walls, overlooking the Alzette and Pétrusse rivers, the crest of the Verlorenkost plateau stands out clearly against the landscape and is now topped with a fine ribbon of glass that highlights the terrain. This is the Police Citadel, so interwoven into the steep slopes of the city that it forms as a natural extension.  The approach to the site was essentially based on landscape and justified by the fragility, visibility and large scale of the project.   Making the most of the site’s inclination, a large platform has been built into the slope and underpinned to free up enough space to accommodate most of the planned facilities. This base visually ties the construction in with the buttresses of the old town opposite. It constitutes a vast promontory, with views over the landscape of the two valleys.  A slender construction on piles outlines the crest of the plateau; this broken line in the landscape, on the same scale as the surrounding transport infrastructure, reveals and underlines the site’s topography while signifying the presence of the Police Citadel. The Citadel is organised into two reference levels: the upper level, accessible from the square, contains the public areas. The lower level contains the internal services, and is in line with the rift running from one end of the base to the other. This rift, mineral and steep at its densest, where the tree foliage above heightens the perception of the slope, rapidly blends in with the green and intimate landscape of the local architectural heritage. From the park that crowns the base, the perception is quite different. The eye is drawn to the full panorama beyond the valleys.