Olympus Mons, and a few other volcanoes, remain above water. Surprisingly, they aren’t even close to being covered. Olympus Mons still rises well over 10 kilometers above the new sea level. Mars has some huge mountains. Those crazy islands are the result of water filling in Noctis Labyrinthus (the Labyrinth of the Night), a bizarre set of canyons whose origin is still a mystery.
