Mentioned by The Crazy Tourist
50 Best Things to Do in San Diego (California
"Founded by the physician Harry M. Wegeforth after he was inspired by the roar of a lion at the Panama-California Exposition in 1915, the San Diego Zoo is rated among the best in the world and houses more than 650 species. This was one of the first zoos to build cageless exhibits, and opened the first ever moated lion enclosure in 1922. You can beat the heat and get around on a guided tour bus that covers three quarters of the park, or the Skyfari tramway from 1969."