Founded in 1962, Phoenix Zoo is the biggest non-profit privately owned zoo in the USA. The zoo has more than 1,400 animals and contains 2.5 miles of walking trails that stretch between four themed areas: the Africa Trail, the Arizona Trail, the Tropics Trail and the Children's Trail, which includes a petting zoo.
Schönbrunn Zoo (German: Tiergarten Schönbrunn; also simply called Vienna Zoo) is a 17-hectare (42-acre) zoo in the city of Vienna, Austria. Established in 1752, it is the world's oldest zoo still in operation.