For this project, our proposal aimed to preserve and enhance the relationship between the existing building and the surrounding landscape. To do so, the new building had to keep a certain distance with the WHO building designed by Jean Tschumi while ensuring optimum connections. In order to strengthen transparency, the building integrates a stilt structure that preserves a public passage through the site and all the uses of the main access level. The existing ground floor and its terrace are then extended and serve as basis for the new extension. The architecture of the new building is compact and clearly organized. It strengthens the qualities of the existing building and is respectful to the environment. Furthermore, the glass surfaces of the new building reflect the natural surroundings of the WHO building. The facades scheme reflects the functional flexibility of the project. The modular grid frame integrates openings with dimensions that increase while approaching the main building. The simplicity and minimalism of the volume express the timelessness and durability of architectural dialogue between the past and the future. Regarding the internal organisation, the new building contains two offices parts with very flexible spaces organized around a large central atrium that includes the vertical circulations (elevators and escalators). On each office floor, meeting and relaxation spaces are organized shifted one from another as a sort of staircase in order to benefit from the zenithal lighting. For this spatial configuration, the atrium is intended to enhance the illumination but also communication, cohesion and the internal life of the new building.