Mount Everest is five and a half miles high. Is there really a mountain somewhere that is fifteen miles high?
Yes. This great mountain is called Olympus Mons, and it sits on the planet Mars. The mountain is a volcano, and the top of it is 45 miles across. How could a mountain ever get so high?
Scientists believe that Mars’ crust doesn’t move the way the earth’s does. On earth, any change in the position of the plates that make up the crust on which a volcano sits shuts off the upward flow of lava.
On Mars, these shifts do not happen, so a volcano can sit on the same stack of lava all its life and just keep on growing higher and higher and higher.
Olympus Mons is also the tallest mountain in the Solar System.