At fifty-three storeys, the Commerzbank is the world’s first ecological office tower and the tallest building in Europe. The project explores the nature of the office environment, developing new ideas for its ecology and working patterns. Central to this concept is a reliance on natural systems of lighting and ventilation. Every office is daylit and has openable windows, which – external conditions permitting – allows occupants to control their own environment. The building is naturally ventilated for 80 per cent of the year and as a result has energy consumption levels equivalent to half those of conventional office towers. The plan form is triangular, comprising three ‘petals’ - the office floors - and a ‘stem’ formed by a full-height central atrium. Four-storey gardens are set at different levels on each side of the tower, forming a spiral of gardens that winds up around the building. The gardens become the visual and social focus for village-like clusters of offices. They play an ecological role, bringing daylight and fresh air into the central atrium, and they are also places to relax during refreshment breaks, bringing richness and humanity to the workplace. From the outside they give the building a sense of transparency and lightness. Depending on their orientation, planting is from one of three regions: North America, Asia or the Mediterranean. The tower has a distinctive presence on the Frankfurt skyline but is also anchored into the lower-scale city fabric. It rises from the centre of a city block alongside the original Commerzbank building. Through restoration and sensitive rebuilding of the perimeter structures, the traditional scale of this block has been reinforced. The development at street level provide shops, carparking, apartments and a banking hall, and forge links between the Commerzbank and the broader community. At the heart of the scheme a public galleria with restaurants, cafés and spaces for social and cultural events forms a popular new route cutting across the site. Interestingly, on the day the Commerzbank opened, the Financial Times adopted it as the symbol of Frankfurt, just as it features Big Ben and the Eiffel Tower as symbols of London and Paris.