Lions, rhinos, chinchillas, elephants, giraffes, cheetahs, a cactus garden, and a million different kinds of dinosaurs - I mean, birds 😉. You have to pay for parking, but you can bring food and drinks into the park. Also, bring your walking shoes!
You can see from the mountains of Mexico to past Torrey Pines State Reserve and all of El Cajon from the top of Cowles Mountain. The Old Mission Dam is a beautiful sight, as is Lake Kumeyaay, and with trails of all levels of difficulty, visiting is something you won't regret.