Geography of Mars Aurorae Sinus. The largest dark feature seen from Earth is Syrtis Major Planum. The shield volcano, Olympus Mons ("Mount Olympus"), rises 22 km above the surrounding volcanic plains, and is the highest known mountain on any planet in the solar system. It is in a vast upland region called Tharsis, which contains several large volcanos. See list of mountains on Mars. The Tharsis region of Mars also has the solar system's largest canyon system, Valles Marineris or the "Mariner Valley", which is 4,000 km long and 7 km deep. Mars is also scarred by countless impact craters. The largest of
Erebor Mons infrared images. It was discovered only when stereoscopic radar data allowed construction of an elevation map. It was imaged by Cassini radar 22 February and 10 April 2007. Erebor Mons is named after Erebor, the "Lonely Mountain" that appears in J. R. R. Tolkien's fictional world of Middle-earth, most prominently in "The Hobbit". The name follows a convention that Titanean mountains are named after mountains in Tolkien's work. The name was formally announced on November 13, 2012. Erebor Mons Erebor Mons is a mountain on Titan, the largest moon of the planet Saturn. It is located near Titan's equator, between