Your next stop is Isabela Island, the largest in the archipelago, where you can opt to visit the wetlands (humedales), to see the local flora and abundant birdlife or to climb the Sierra Negra Volcano which offers breathtaking views over the contrasting colors of the lava fields. Keep an eye out for the giant tortoises and marine iguanas that you may see on the way up Orchilla Hill. Your next stop is the Arnaldo Tupiza Breeding Center, where you can see infant and juvenile giant tortoises before they are released into the wild. Alternatively, visit the Wall of Tears, which was built in the 40s by prisoners when Isabela Island was a penal colony. On the way back to your vessel, look out for flamingos and other water birds.