Start the morning with an exhilarating hike to the summit of Bartolome Island, where surreal volcanic landscapes stretch as far as the eye can see. Pinnacle Rock rises dramatically from the turquoise waters, and the rugged surroundings feel almost extraterrestrial. Afterward, snorkel among playful penguins, reef sharks, rays, and schools of colorful fish. In the afternoon, step onto Sullivan Bay’s lava fields, where you can walk across smooth Pahoehoe formations that look like frozen rivers. Here, life clings to the rocks, with lava lizards and pioneer plants making a tough existence amid the volcanic desolation.