The tower takes root in a bay, in the bend of a river, in a lake ... in the heart of the city. A network of pipes mesh in the infrastructure tissue, collects the polluted air along the expressways and in the industrial zones. This network joins at the Rainbow Tower, whose base is made of a treatment plant intended to humidify the air to a misty state. This polluted semi-liquid substance then invests the fibre textile up the structure by capillarity. The composite fabric, therefore, makes it possible to filter the air and purify it by separating the elements. The filtered pollution clings to the fabric. The purified air is expelled, melt with vaporized water. Mists spread through the light fur, sensitive to the movements of winds and breezes. In nature, the constant movement of wind in the mountains and in the forest, the movements of water dropping down a waterfall, the movement of rivers and branches in the trees naturally create negative ions purifying and refreshing the air. The well-known sense of well-being in the mountains, in a forest, near a river or a torrent, is directly linked to the large concentration of negative ions in these places. Populating the structure of the construction, fans spread this sweet sensation of pure air in the megalopolis. An essential fragrance for the city to have happy city dwellers. Beyond the symbol of the megalopolis in perpetual growth, Tokyo already identifies today the systemic problems that will meet the cities of the world of tomorrow: unhealthy air, saturated networks... The Rainbow Tower is implanted in a node, in one of the wheels of the mechanisms of Tokyo. It concludes the monumental composition of the Rainbow Bridge, as a fixed point in the visible movements of the city working at the quality of elusive flows.