North panoramic view of the Citlaltépetl (Pico de Orizaba) volcano. The volcanic edifice shows some irregularities on its flanks, which represent the remnants of the ancient cones on both flanks, on which the present cone was built. This is the highest North American volcano (5685 m a.s.l.), still active with the only glacier preserved in Mexico. See the related article in this issue; photograph courtesy of the author: Gerardo Carrasco-Núñez.