The Washington Park Amphitheater is located in the Rose Garden and hosts many public concerts, including the Washington Park Summer Festival, an annual free concert series normally presented in August.[16] The Hoyt Arboretum contains nearly 6,000 individual trees and shrubs of over 2,000 species on 153 acres (62 hectares) and was founded in 1928.[17] Twelve miles (19 km) of Washington Park's trails are located in the arboretum.[18] The Oregon Zoo, which opened at its current site in 1959, contains more than 2,500 animals of more than 200 species (including 15 endangered and 7 threatened species) in natural or semi-natural habitats.[19] The zoo has a notable Asian elephant breeding program that grew out of the birth in 1962 of Packy, who in adulthood was the largest example of the species in North America.