olimpus mons located on mars is 86,000 feet high (26,212.2 m) it is the most exenct volcano and the biggest exencit volcano ever known to man.
Mauna Loa, Hawii
they have not erupted in a long time and are not expected to erupt.
No there are many other extinct volcanoes that are larger.
If volcano is extinct then it is possibly "dead". It wouldn't have erupted in a million years take or give some.
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