<Tr> <Th> Discoverer </Th> <Td> Mariner 9 </Td> </Tr> <Tr> <Th> Eponym </Th> <Td> Latin--Mount Olympus </Td> </Tr> <P> Olympus Mons (/ əˌlɪmpəs ˈmɒnz, oʊ -, - ˈmɒns /; 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 (13.6 mi or 72,000 ft). Olympus Mons is about two and a half times Mount Everest's height above sea level . It is the largest volcano, the tallest planetary mountain, and the second tallest mountain in the Solar System compared to Rheasilvia on Vesta . It is the youngest of the large volcanoes on Mars, having formed during Mars's Hesperian Period . It 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 . </P> <P> The volcano is located in Mars's western hemisphere at approximately 18 ° 39 ′ N 226 ° 12 ′ E ﻿ / ﻿ 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). </P>

What is the name of the highest mountain on mars