Where is the largest volcano in the solar system?
The largest volcano in the solar system, also the largest mountain in the solar system, is on Mars.
The largest volcano is called Olympus Mors, a shield volcano, which towers to heights of 26 km, making this volcano over three times as large as Mt Everest. Unlike Everest, Mors has a very gentle slope, and reaches up to 550 km wide at its base. The edge of this volcano is marked by a basal cliff that is over 6 km high in some locations, but has been destroyed by the martian lava flows in the past.