1958 marked an international breakthrough when Kühn's work was included in the "West" German pavilion display at the Brussels World Fair, forging for it an "artistically forged mesh element, inspired by an x-ray of a human chest". Even after the sudden appearance of the Berlin Wall in 1961, Kühn was seen as a member of the artistic establishment, winning commissions from state authorities and respected for his inventive artistry in his unusual artistic niche, on both sides of the so-called iron curtain, despite the increasing semblance of permanence in the physical and political divisions between East and West Germany. The listing of his commissioned works in public space now extended to 220 projects. His iron-based artworks featured, not just in the German Democratic Republic but also in places such as Hannover, Dortmund, Saarbrücken and Düsseldorf. Further afield, he also contributed to the war memorial at Coventry and the vast Futa Pass Cemetery in the Apennines between Bologna and Florence. It was also in 1958 that back in Berlin he succeeded in obtaining the necessary agreements to buy his studio-workshop and the adjacent former paddock.