 In 1958, a facility for penguins and seals was dedicated by businessman and promoter Helmut Horten.In 1965, one of Europe’s largest dolphinariums was opened in a newly developed area.Research into the behavior of dolphins increased the zoo’s prestige, but also drew sharp criticism, since even the generously dimensioned dolphinarium only managed to offer a small fraction of the space available to a dolphin in its natural habitat.