Olympus (lat. Olympus Mons) - an extinct volcano on Mars, the highest mountain in the solar system. Prior to the flight of spacecraft (which showed that Olympus - the mountain) the place was known to astronomers as Nix Olympica («Snow Olympus" - due to a higher albedo).
The height of Mount Olympus - 27 miles to the base and 25 km to the average level of the surface of Mars. This is several times higher than the highest mountains in the world. Olympus extends to 540 km wide and has steep slopes at the edges up to 7 km. Reasons for the formation of these giant cliffs have not yet found a convincing explanation.