The San Antonio Zoological Gardens and Aquarium is an Association of Zoos and Aquariums-accredited zoo in Midtown San Antonio, Texas, United States. The 35-acre (14 ha) zoo has a collection of over 3,500 animals representing 750 species. The zoo's annual attendance exceeds 1,000,000. It also runs non-animal attractions, such as the 2 ft (610 mm) narrow gauge San Antonio Zoo Eagle train ride, which first opened in 1956 and utilizes three Chance Rides C.P.