Tharsis quadrangle Mount Everest and about as big in area as all of Europe. Tharsis contains a group of large volcanoes. Olympus Mons is the tallest. Tharsis is a land of great volcanoes. Olympus Mons is the tallest known volcano in the Solar System; it is 100 times larger than any volcano on Earth. Ascraeus Mons and Pavonis Mons are at least 200 miles across and are over six miles above the plateau that they sit on—and, the plateau is three to four miles above the zero altitude of Mars. Pavonis Mons, the middle in a line of three volcanoes, sits at
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