On 29 June 1929 the “Große Ruhrländische Gartenbau-Ausstellung” (Great Ruhr Landscape Gardening Exhibition) opened, which was soon named after its German abbreviation – Gruga. The artistic garden architecture attracted millions of visitors to the blooming garden in the middle of the industrial region. The 25 hectare exhibition site was planted in a strictly delineated three axis system. The planned garden architecture with Colour Terraces, the Dahlia Arena, Gruga Tower and water features amazed the visitors. In 1938 the park was enlarged to 47 hectares for the “Reich Garden Show”. The Gruga Rail and the Children’s Zoo were also added.
During the Second World War the Grugapark was largely destroyed but as early as the end of the 40s it had been reopened in part. In 1952 a second “Große Ruhrländische Gartenbau-Ausstellung” took place. The formerly strict geometry made way for a more freely designed landscape with gently rolling lawns and generous panoramas.