Arsia Mons of the features shows sunlight illuminating a side wall, suggesting that it may simply be a vertical pit rather than an entrance to a larger underground space. Nonetheless, the darkness of this feature implies that it must be at least 178 meters deep. Arsia Mons Arsia Mons is the southernmost of three volcanos (collectively known as Tharsis Montes) on the Tharsis bulge near the equator of the planet Mars. To its north is Pavonis Mons, and north of that is Ascraeus Mons. The tallest volcano in the solar system, Olympus Mons, is to its northwest. Its name comes from a
Maat Mons Maat Mons Maat Mons is a massive shield volcano. It is the second-highest mountain, and the highest volcano, on the planet Venus. It rises above the mean planetary radius at , and nearly 5 km above the surrounding plains. It is named after the Egyptian goddess of truth and justice, Ma'at. Maat Mons has a large summit caldera, 28×31 km in size. Within the large caldera there are at least five smaller collapse craters, up to 10 km in diameter. A chain of small craters 3–5 km in diameter extends some 40 km along the southeast flank of the volcano,