Mars is the planet that has the largest volcano, known as Olympus Mons. This impressive shield volcano is approximately 22 kilometers (13.6 miles) high, making it nearly three times taller than Mount Everest, Earth's highest peak. Olympus Mons spans roughly 600 kilometers (373 miles) in diameter and is surrounded by a steep cliff several kilometers high. Its size and unique geological features have fascinated scientists, providing insights into volcanic activity on Mars and the planet's historical geology. Olympus Mons is a significant topic in discussions regarding Mars exploration and planetary sciences.