Olympus Mons is a giant shield volcano on the planet Mars. The volcano has a height of over 21 kilometers (13.6 miles). It is approximately 2.5 times Mount Everest’s height above sea level.
The volcano’s diameter is about 374 miles or 624 kilometers (the same size as the state of Arizona) and is rimmed by a 4 miles (6 km) high scarp. It is the largest volcano discovered in the Solar System.
The maps below show Olympus Mons compared to Australia, France and the U.S. state Arizona.