One of the largest, most diverse and most celebrated zoological parks in the world, the San Diego Zoo occupies 100 acres of lushly landscaped hillsides and ravines at the northern end of Balboa Park. Some 4,000 animals represent 800 different species in a setting shaded by plants representing more than 6,500 botanical species, many of them subtropical.During the Panama-California Exposition, a small menagerie of wild animals was assembled near the eastern edge of Balboa Park, just northeast of the zoo's present location. The roar of a caged lion there inspired local surgeon Dr. Harry Wegeforth, who had a lifelong passion for circus animals, to found the Zoological Society of San Diego, which began its collection with specimens gathered from the various exhibits at the close of the fair. In 1922 the city granted the society its permanent home-a hilly, chaparral-covered tract of 100 acres. In subsequent years the San Diego Zoo has been a pioneer in creating humane enclosures for its animals and saving endangered species. Major exhibits include Tiger River, a winding trail descends through a misty tropical rain forest, passing crocodiles, fishing cats, tapirs, pythons, and tigers; the Ituri Forest, a Central African rain forest that displays okapi, forest buffalo, spotted-necked otters, monkeys and birds; and the Giant Panda Research Station, which houses the zoo's premier exhibit: a family of giant pandas on loan from the People's Republic of China.