A large tuff cone occupies the ENE side of the summit caldera of Cerro Azul volcano at the SW tip of Isabela Island. A small caldera bench is seen above the cone at the upper right, and a larger bench on the northern side of the caldera is outlined by the light-colored line below the horizon at the upper left. The 4 x 5 km wide caldera is one of the smallest of the Galápagos shield volcanoes, but its 650 m depth makes it one of the deepest. Youthful dark-colored lava flows at the left cover much of the caldera floor. Photo by Tom Simkin (Smithsonian Institution).