An extension to the Historical Museum Bern, that was built by André Lambert in 1894 in an historic style that invokes Swiss architecture of the 15th and 16th century, this project is composed of two distinct elements. A 1000m2 temporary exhibition hall located beneath a new civic square and a monolithic six storey block along the southern side of the site that houses the Bern city archives, offices and a library. In the part under the square, the exhibition space is a double high ‘black box’ space suitable for a range of different visiting exhibitions. In close proximity, below the exhibition space, there are two levels for the storage of artifacts in secure climate controlled conditions. This relationship of archive and exhibition space facilitates the easy care and display of collections. The second element has two very different faces. Towards the square the building presents a transparent orthogonal modernist curtain wall. The activities within the building are clearly visible. In contrast the south façade rises up - a folded cliff of cast concrete, punctured by small random openings and indentations. This concrete skin wraps around the building embracing and sheltering its contents. Behind the south wall, in a vertical slot, a triple height staircase connects the floorplates. Outside a sweep of board steps rise up to the square in front of the glazed north façade.