Olympus Mons is a fascinating geological feature and holds the title of the largest volcano and highest planetary mountain in the Solar System. Olympus Mons reaches a towering height of about 22 kilometers. This makes it nearly three times the height of Mount Everest, which is approximately 8.8 kilometers tall. Mars has about one-third of Earth’s gravity, which allows volcanic structures to grow taller before they collapse under their own weight. This low gravity helps support the immense height of Olympus Mons.