In lectures at academies and before architectural associations, Hundertwasser elucidated his concerns regarding an architecture in harmony with nature and man. Bruno Kreisky, the federal chancellor at the time, suggested in a letter dated November 30, 1977 to Leopold Gratz, the mayor of Vienna, that Hundertwasser be given the opportunity to realize his ideas in the field of architecture by allowing him to build a housing project, whereupon Leopold Gratz, in a letter of December 15, 1977, invited Hundertwasser to create an apartment building according to his own ideas.