The Duisburg Zoo, founded on 12 May 1934, is one of the largest zoological gardens in Germany. It is especially well known for its dolphinarium and, since 1994, for breeding koalas. Far less well known are the breeding successes in other areas, for example, with fossas (civits from Madagascar) and red river hogs. The zoo is located in the northern part of the Duisburg urban forest on the border with Mülheim on the Ruhr. Federal highway A 3 divides the zoo into western and an eastern parts, which are joined by a leafy country bridge. The highway is scarcely noticeable to the visitors.