Spodek, Katowice

Katowice's coal seams run directly beneath the city centre, and any building set there has to survive the tremors of mining subsidence. A closed 1959 competition for a hall to replace an earlier venue asked for exactly that, and the entry from architects Maciej Gintowt and Maciej Krasiński, developed with structural engineer Wacław Zalewski, answered with a shape rather than a cage: an inverted concrete cone standing on forty flexible supports, roofed by a saucer of 120 radial steel cables strung from a central ring and anchored to a reinforced concrete rim, so the whole structure can flex under a shock instead of resisting it rigidly. It was among the first tensegrity roofs attempted anywhere at this span. Ground was broken in 1964; the hall opened on 9 May 1971, seating over ten thousand under a dome unbroken by any internal column. Katowice nicknamed it Spodek, the saucer, well before it was finished, and the name displaced whatever the commission had originally intended to call it.