Io's surface is marked with volcanic features and mountains. This Voyager 1 mosaic covers Io's south polar region. At the bottom of the image is Haemus Mons, 1 10 km. high mountain. The rest of the image is typical of Io, with flat volcanic plains, eroded volcanic plateaus, and cratered volcanic calderas. Image Credit: By NASA / Jet Propulsion Laboratory / USGS - http://photojournal.jpl.nasa.gov/catalog/PIA00327, Public Domain, https://commons.wikimedia.org/w/index.php?curid=18530344