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
Tohil Mons Tohil Mons Tohil Mons is a mountain on Io, one of Jupiter's moons. It stands at 5400 m (18,000 feet) and is located in the Culann–Tohil region of Io's antijovian hemisphere. It was named after the Mayan weather god Tohil. Tohil Mons is one of the most geologically complex mountains in the Solar System as the mountain shows evidence of forming from other mountains through tectonic and erosional processes, in combination with silicate volcanic rock or magma activity. The main massif of Tohil Mons has ridges and grooves, which indicate the presence of materials that have been tectonically displaced, including