Olympus Mons is a very large shield volcano on the planet Mars. The volcano has a height of nearly 25 km as measured by the Mars Orbiter Laser Altimeter. Olympus Mons is about two and a half times Mount Everest's height above sea level.

Dimensions: Tallest planetary mountain in the Solar System

Peak: 21,287.4 m (69,841 ft) above datum; 26 km (85,000 ft) local relief; 26 km (85,000 ft) above plains

Discoverer: Mariner 9