In 1961 the director of the Museum Haus Lange in Krefeld, Paul Wember, realized his biggest wish: he presented a major exhibition of his favourite artist Yves Klein - the only museum exhibition of the artist during his lifetime - who died the following year. The sponges could be acquired during the exhibition.
"With the sponges – living, wild material – I was able to create portraits of the readers of my monochromes, who, after they had travelled through the blue of my paintings, were - like the sponges - completely impregnated by the sensibility." The blue colour, developed and patented by the artist himself (IKB= International Klein Blue) to him was a symbol of eternity. He exhibited the first blue sponge sculpture in May 1957 in the exhibition "Propositions monochromes" at Galerie Iris Clert in Paris. Soon afterwards he integrated natural sponges in his monemental murals for the Theater Gelsenkirchen (1958-59). In the summer of 1959 he exhibited blue sponge sculptures, with and without stand at Galerie Iris Clert in an exhibition titled "La fôret d’éponges" (Forest of sponges).
