Extension of the WHO Headquarters
Building on a Classic Legacy: An Invisible Extension
Our fundamental concept — which evolved graduall with our design for the new extension — was to respect and to create a dialogue between two existing but contrasting elements: Jean Tschumi’s original creation and the wide, open green spaces of its setting. A masterpiece of modern architecture, Tschumi’s design — now 50 years old, and weathering beautifully — has three distinct elements: a linear office block hovering above the access level and a spiral pavilion structure that connects downwards to a lower volume, which orders and defines the limits of the ensemble.
We wanted to create a design that would not challenge Tschumi’s concept — by being too large or too close — and so would have an ‘invisible’ impact: increasing the usable room space, but adhering to the current site curtilage. It would provide fine, functional, and flexible spaces in which people could work and gather, concentrate and relax; spaces that were easily accessible and naturally lit, but would embrace and integrate the whole campus opening it out to the local parkland.
The principal element of our proposal is a single, new, L–shaped horizontal volume whose two wings define the site’s edges. Its restrained scale facilitates uninterrupted views of the surrounding landscape from the existing offices, and its ‘invisible’ green roof turfed with grass and shrubs creates a terrace garden, with edges that seem to be carved into the landscape, drawing nature inside. Extending outwards, it serves as a walkway into the panorama, giving clean views back to the main building.
In the wider context, this roof garden connects the site seamlessly to the neighborhood’s disparate elements — the proposed forecourt esplanade north of the existing building and the parkland south of the site. A discreet ramp on its western edge gives vertical circulation to the offices below and to Appia Parkway, while a bridge links to the park creating generous public spaces that accommodate bicycle and pedestrian paths.
Nestled into the park’s gently sloping landscape, the new additions adopt the scale of the ensemble’s existing buildings, and the structural rhythm of the office volumes complement the existing spiral pavilion structure. Buildings, topography and landscape are held in harmony, erasing the site’s boundaries and achieving a fluid transition from built spaces to the landscape, which allows both to be experienced together.
The proposed new extension marks a fresh stage in the development of this important site. It offers considerably enhanced working and public spaces, enshrines today’s eco-imperatives, and opens the site up to the landscapewhile still paying tribute to Tschumi’s legacy.