SPACEPHOTOS

This unusually cloud-free, near-vertical photograph shows the two most volcanically active islands in the Galápagos—the smaller, roughly round Fernandina in the center of photograph and seahorse-shaped Isabela in the top right corner. A clear view of seven calderas is provided. The most recent lava flows are the dark areas crossing the older, sparsely vegetated flows (lighter areas). An abrupt steepening of the slope, which characterizes the Galápagos volcanoes, is especially noticeable at Wolf Volcano (the northernmost, water-filled crater). The Galápagos Islands, a wildlife sanctuary, are located in the Pacific Ocean at the Equator, 600 miles (1000 kilometers) west of Ecuador. Charles Darwin visited these islands, studied the species of animal life, and subsequently developed his theory of natural selection.