As a competition entry for the Scandinavian pavilion at the expo exhibition in Osaka 1970, architect Sverre Fehn proposed a moving, inflatable structure, where powerful images of Scandinavian nature were to be projected on its expanding and contracting walls. His intention was to communicate the problem of industrial pollution vs. the purity of nature and to create a concrete architectural narrative that would disseminate the Scandinavian message through the form of space. The solution was a huge inflatable structure 45 m long and 24 m high, precisely erected within the limitations of a building frame that had already existed on the site. The construction was imagined as an artificial lung, consisting of two interacting balloons, which would, similarly to the breathing process, visualize the clean atmosphere inside as opposed to the polluted world outside. The lower balloon had a constant pressure and the upper balloon, varied by the changing pressure of the air, was constantly changing the form of the underlying balloon – the main exhibition space. The fresh circulating air was pumped into the balloons by a mechanical tower outside the structure. Both balloons were made of transparent flexible material, with a wooden pier in the interior. One entrance and one exit directed the circulation of about 100 visitors through space at the time.