For all things green and prickly, find your way to Old Cactus Garden. Discover why desert plants like succulents, shrubs and cactuses are able to survive in dry, desolate environments.
Wandering around this collection of desert plants won't cost you a dime, which is great news if you're chasing free things to do. You'll find Old Cactus Garden in Birdland. There are loads more attractions to enjoy in the area, including SeaWorld, San Diego Zoo and Balboa Park.