The Bronx Zoo is located in the Bronx, a borough of New York City, within Bronx Park. It is among the largest metropolitan zoos in the world, and is one of the largest in North America, with some 4,000 animals representing about 650 species from around the world. The zoo comprises of park lands and naturalistic habitats, through which the Bronx River flows. The Bronx Zoo is part of an integrated system of four zoos and one aquarium managed by the Wildlife Conservation Society (WCS), and is accredited by the Association of Zoos and Aquariums (AZA).