The Galápagos Islands are a scatter of volcanic islands a thousand kilometres off the coast of Ecuador, in the Pacific, and their fame rests on one fact: the animals here never learned to fear people. Sea lions sleep on the white beaches you walk along and barely lift their heads. Black marine iguanas, the only lizards on Earth that feed in the sea, pile together on the dark lava to warm up between dives and let you step round them. On the trail a male blue-footed booby lifts each turquoise foot in turn, tips his bill to the sky and whistles at a female a few steps from you. In the cool green highlands of Santa Cruz, giant tortoises graze and wallow in muddy pools, some of them older than anyone watching. Penguins fish in water on the equator, the only penguin that lives this far north. Charles Darwin spent five weeks here in 1835 and noticed that the finches and tortoises differed from island to island; the idea that grew from that changed biology.
The islands are still being made. They sit over a hotspot in the Earth's crust and ride slowly eastward off it, so the western islands are the youngest and still erupt, and the landscape is raw: black lava fields, red and brown cinder cones, cactus growing out of rock. The most famous view is from the wooden steps up Bartolomé Island, beside Pinnacle Rock, a jagged spire above a curve of sand and turquoise water. The sea is half the visit. Snorkelling puts you among sea lions that twist around you to play, green turtles and rays, and in the warm months around March the water is at its clearest. Almost the entire world population of waved albatross nests on Española, landing from late March and dancing through April. Far to the north, at Darwin and Wolf, whale sharks pass between June and November, almost all of them female, and nobody yet knows why they come. In the Galápagos the questions Darwin started asking are still open, and the animals still walk up to you.