A Sally Lightfoot crab on the volcanic shore of Isla Isabela — the largest island in the Galápagos archipelago — with the Pacific surging behind it. Against the dark lava, the red is almost violent. These crabs are everywhere in the Galápagos and completely indifferent to humans, which is the only reason you can get this close. Eye to eye with something that has lived here, unchanged, for millions of years.