Olympus Mons the height of Mauna Kea as measured from its base on the ocean floor). The total elevation change from the plains of Amazonis Planitia, over to the northwest, to the summit approaches . The summit of the mountain has six nested calderas (collapsed craters) forming an irregular depression × across and up to deep. The volcano's outer edge consists of an escarpment, or cliff, up to tall (although obscured by lava flows in places), a feature unique among the shield volcanoes of Mars. Olympus Mons covers an area of about , which is approximately the size of Italy, and it
Erebor Mons Erebor Mons Erebor Mons is a mountain on Titan, the largest moon of the planet Saturn. It is located near Titan's equator, between 4-5° south and 35-36° west, centered on , in the western part of Quivira region. It is 40 km across, more than 1 km high and has lobate flow features to its north and east. It is probably a cryovolcano. Erebor Mons is situated about 470 km to the north-northeast of a larger cryovolcanic construct, Doom Mons. Erebor Mons is one of the highest known mountains of Titan, but it is not readily discernible on radar or