This tape contains the electronic piece titled Zoologischer Garten, composed by American composer Frederick Rzewski in the Labor für Akustisch-Musikalische Grenzprobleme between August and December 1965. In 1965, Rzewski was a fellow of the Ford Foundation in West Berlin, and due to his socialist political inclinations, he accepted Gerhard Steinke’s invitation to collaborate with the GDR’s laboratory for electroacoustics. Rzewski’s 23-minute composition, created with the Subharchord (the GDR’s first electronic synthesizer), was recorded in the Labor für Akustisch-Musikalische Grenzprobleme and was meant to be transmitted via radio to East and West Germany, in what would have been the first electronic music concert broadcast by East German radio. Due to various political reasons, the transmission never took place, and the piece remained unpublished until today.