On the eastern slopes of Letná hill, overlooking the Vltava, this unusual modernist structure looks as if it has been teleported from some future time into its present location. In actual fact that’s not far off the truth. Originally designed for the World Fair of 1958 in Brussels, the lightweight glass and steel structure with its distinctive raised rotunda successfully combined a pleasing aesthetic with novel technologies and construction techniques. Its modular system allowed it to be simply erected and dismantled, a requirement of the project brief. Visited by 6 million people and winner of the Grand Prix for best pavilion, it must have been with some pride that the building was taken down and transported to its new location