Originally opened in 1915, the San Diego Zoo has become one of the largest and most famous zoos in the world. The zoo holds over 4,000 animals on 100 acres of land, which includes a botanical garden, African rainforest and free-slight aviaries. Among the animals here are gorillas, giant tortoises, giant pandas and many endangered species. Visitors can view the park via a tram, sky-lift or bus tour, and spend an entire day touring the 10 separate environmental habitats. view all details