At the northern end of San Cristóbal is Los Galápagos, where you can often see giant Galápagos tortoises in the wild, although it does takes some effort to reach the highland area where they live.
One way to reach Los Galápagos is to land in a bay at the north end of the island and then hike up – it takes about two hours to get to the tortoise area following the trail. Some visitors report seeing many tortoises, while others see none.