Largest walk-through zoo

The world's largest walk-through zoo is the North Carolina Zoological Park (aka North Carolina Zoo), situated in Asheboro, Randolph County, North Carolina, USA. Over 810 hectares in total area, it is home to more than 1,600 animals, representing some 250 different species, particularly ones from North America and Africa, and including a lauded aviary. It was officially opened on 13 August 1974, and averages over 700,000 visitors annually.

North Carolina Zoo is one of only two state-owned zoos in the USA (the other one being Minnesota Zoo), and has a number of claims to zoological fame, including being home to the largest collection of chimpanzees in any US zoo and also the largest collection of Alaskan seabirds in captivity in the USA. It was also home to Ham the chimpanzee astronaut, famous for being launched into space on 31 January 1961, until his death from a heart attack on 19 January 1983, aged 25.