Marine Mammal Center, on the hill above Rodeo Lagoon, is the largest marine mammal hospital in the world. In 2009 the center opened its all-green, solar-powered hospital, with observation decks for visitors to get close to the recovering patients (mostly seals and sea lions) before they’re released back into the wild. Spring brings oh-so-cute new pups – and the most visitors. Kids love the hands-on exhibits and see-through glass walls to the science labs and animal rooms.