More than 4,000 creatures reside at this celebrated zoo, started in 1916 and run by the Zoological Society of San Diego. In the early days, the zoo's founder, Dr. Harry Wegeforth, traveled around the world and bartered native Southwestern animals such as rattlesnakes and sea lions for more exotic species. The zoo is also an accredited botanical garden, lavished with more than 1 million plants on its 1,900 acres; "Dr. Harry" brought home flora from every location where he acquired animals, ensuring what would become the zoo's naturalistic and mature environment.

The zoo is one of only four in the United States with giant pandas -- including the most recent arrival, Yun Zi, who was born here in 2009. Many other rare species are here as well, including Buerger's tree kangaroos of New Guinea, long-billed kiwis from New Zealand, wild Przewalski's horses from Mongolia, lowland gorillas from Africa, and giant tortoises from the Galapagos.

Monkey Trails and Forest Tales is the zoo's largest, most elaborate habitat, re-creating a wooded forest full of endangered species such as the mandrill monkey, clouded leopard, and pygmy hippopotamus. An elevated trail through the treetops allows for close observation of the primate, bird, and plant life that thrive in the forest canopy. Absolutely Apes showcases orangutans and siamangs (black-furred gibbons) of Indonesia, while next door is Gorilla Tropics, where two troops of Western lowland gorillas roam an 8,000-square-foot habitat. Despite the hype, the Giant Panda Research Center is not worth the hassle when there's a long line (lines are shortest first thing in the morning or toward the end of the day). More noteworthy are Ituri Forest, which simulates a central African rainforest with forest buffalos, otters, okapis, and hippos (viewed underwater from a glassed-in enclosure); and the renovated Polar Bear Plunge, which also offers below-the-waterline perspectives and interactive elements. The Children's Zoo features a nursery with baby animals and a petting area where kids can cuddle up to sheep, goats, and the like; there's also a sea lion show at the 3,000-seat amphitheater (easy to skip if you're headed to SeaWorld). Opened in 2009 is Elephant Odyssey, which displays a herd of Asian elephants as well as life-size replicas of prehistoric animals that roamed Southern California; you can also watch handlers interact with the pachyderms at the elephant care center.

If a lot of walking -- some of it on steep hills -- isn't your passion, a 35-minute Guided Bus Tour provides a narrated overview and covers about 70% of the facility; it's included with the price of admission. Since you get only brief glimpses of the enclosures, and animals won't always be visible, you'll want to revisit some areas. Also included with admission is access to the un-narrated Express Bus, which allows you to get on and off at one of five different stops along the same route; a park overview is available from the Skyfari aerial tram, as well, though you won't see many creatures. An ideal plan is to take the complete bus tour first thing in the morning, when the animals are more active (waits for the bus tour can be long on a busy day); after the bus tour, take the Skyfari to the far side of the park and wend your way back on foot or by Express Bus to revisit animals you missed. Other zoo experiences include sleepovers and Backstage Passes ($99), a 1 1/2-hour, behind-the-scenes tour (ages 5 and up) that includes interacting with animals and trainers; call tel. 800/407-9534 or 619/718-3000 for more information and reservations.

In addition to several fast-food options, Albert's restaurant is a beautiful oasis at the lip of a canyon and a lovely place to take a break.