The Popocatepetl. These two Mexican volcanoes, with the famous Popocatepetl, left, and the Iztaccíhuatl, right, both belong to the famed "Ring of Fire" which is circling the Pacific Ocean. Various tectonic plates plunging under each other are generating deep oceanic trenches, as, some miles inland, high mountainous, volcanic range are rising, just like in New Guinea, Japan, Alaska, or in South America. "Popocatepetl" means "smoking moutain" in Aztec, as "Iztaccíhuatl", "Woman in White". A faint plume is seen at the summit of the Popocatepetl, which is reminding that the volcanoe is an ever-present hazard to the neighbouring regions, of them Mexico City. This picture was taken from aboard the International Space Station (ISS), this low-Earth orbiting, international space lab. As it originated like a 16 nations partnership mainly, the ISS has now been enlisted to the service of the new US "Vision for Space Exploration" targeting the Moon and Mars. The ISS will be providing an experimental field for the effects of long-duration spaceflights. The ISS is orbiting at an altitude of about 230-218 miles (370-350 km) above the Earth, with an inclination of 52° to equator. It takes 90 minutes to the ISS to complete one of its orbits. picture NASA