Mons Olympus, the tallest known volcano, and mountain, in the solar system, is one of many large volcanoes on Mars.
Mons Olympus is about 27 km tall, and can be found in the vast upland region Tharsis, which contains several other large volcanoes.
Mons Olympus is Latin for “Mount Olympus”, and is believed to have formed during Mars’ Amazonian epoch.
It is considered extinct, but some volcanoes may still be active.
We have no proof one way or the other at this time.