This 142-metre-high headquarters of a water-supply undertaking was designed like a “fluid mass that shoots out of the ground under constant pressure”, avoiding the strict verticality of most skyscrapers and at the same time reflecting the link with water. In an interplay of light, transparency and colour, the multi-layer facade lends the building a diffuse, vibrant quality. A load-bearing concrete outer wall, punctuated by 4,500 window openings in an irregular arrangement, provides a good thermal shield. The wall is clad on the outside with coloured aluminium sheeting, and 90 cm in front of this is a layer of more than 56,000 glass louvres that can be inclined at various angles. The blue and red colours that shimmer through this skin become increasingly subdued towards the top, eventually turning to white and finally giving way to a fully glazed dome. The space between the facade layers forms a thermal buffer and allows a natural circulation of air and ventilation.