Olympus Mons is a shield volcano — the same broad, gently-sloped type as the Hawaiian volcanoes here on Earth.
But on a scale that has no comparison.
It rises 21.9 kilometers above the Martian surface.
That's nearly two and a half times the height of Mount Everest above sea level.
And it is so wide — 600 kilometers across — that it would cover the entire state of Arizona.
And at its base, it is surrounded by a cliff.
An escarpment up to 8 kilometers high.
Eight kilometers.
Taller than any mounta