National Zoological Park (Parque Zoológico Nacional) is at Ave. Vega Real and Ave. Los Arroyos Arroyo Hondo. The zoo preserves the natural environment of a wide variety of animals, which are allowed to roam freely. The park includes the African Plain, a children's zoo and one of the largest bird cages in the world. Five miles (8 km) of roads and walks traverse the park. Train tours also are available.