Olympus Mons /ɵˌlɪmpəs ˈmɒnz/ (Latin for Mount Olympus) is a very large shield volcano on the planet Mars. By one measure, it has a height of nearly 25 km (16 mi). Olympus Monsstands almost three times as tall as Mount Everest's height above sea level. It is the youngest of the large volcanoes on Mars, having formed during Mars's Amazonian Period. It is currently the largest volcano discovered in the Solar System and had been known to astronomers since the late 19th century as the albedo feature Nix Olympica (Latin for ""Olympic Snow""). Its mountainous nature was suspected well before space probes confirmed its identity as a mountain.The volcano is located in Mars's western hemisphere at approximately 18.65°N 226.2°E / 18.65; 226.2, just off the northwestern edge of the Tharsis bulge. The western portion of the volcano lies in the Amazonis quadrangle (MC-8) and the central and eastern portions in the adjoining Tharsis quadrangle (MC-9). Two impact craters on Olympus Mons have been assigned provisional names by the International Astronomical Union. They are the 15.6 km (9.7 mi)-diameter Karzok crater (18°25′N 131°55′W) and the 10.4 km (6.5 mi)-diameter Pangboche crater (17°10′N 133°35′W). The craters are notable for being two of several suspected source areas for shergottites, the most abundant class of Martian meteorites.