Major differences between the Shuttle Radar Topography Mission (SRTM) elevation model generated in 2000 and the current TanDEM-X elevation model are shown in colour on this TanDEM-X radar image of Mount Etna. The differences are due partly to the finer variations in elevation that SRTM could not reveal and partly due to new lava flows and a change in the altitude of the crater. One such outflow, from 2001, is visible to the south (left), while most of the changes in the central 'Valley of the Ox' (Valle del Bove) are of more recent origin.