The Bronx Zoo is located in the Bronx borough of New York City, within Bronx Park. It is the largest metropolitan zoo in the United States, comprising 265 acres (107 ha) 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).
The zoo (originally called the Bronx Zoological Par and the Bronx Zoological Gardens) opened its doors to the public on November 8, 1899, featuring 843 animals in 22 exhibits. The first zoo director was William Temple Hornaday. Heins & LaFarge designed the original permanent buildings as a series of Beaux-Arts pavilions grouped around the large circular sea lion pool. In 1934, the Rainey Memorial Gates, designed by noted sculptor Paul Manship, were dedicated as a memorial to noted big game hunter Paul James Rainey. The gates were listed on the National Register of Historic Places in 1972.
In November 2006, the Zoo opened up brand-new eco-friendly restrooms outside the Bronx River Gate. According to the Clivus multrum company, which built the composting toilets chosen by the Zoo, these facilities will service 500,000 people and save 1,000,000 U.S. gallons (3,800,000 l) of water a year.