Oh god, no one really knows that answer ...
But anywho, i'd have to say Mt. Mauna Kea in the Asia Pacific region, for even though other mountains might have been bigger, such as K2, Mt. Mauna Kea technically is the highest, for its the tallest mountain from base to top.
If the answer is something like Mt. Everest, because it was still the tallest but not yet discovered, then can you at least warn us if it's a trick question
Edit: That's my answer btw -- Mount Everest, incase you didn't catch the last part.
But anywho, i'd have to say Mt. Mauna Kea in the Asia Pacific region, for even though other mountains might have been bigger, such as K2, Mt. Mauna Kea technically is the highest, for its the tallest mountain from base to top.
If the answer is something like Mt. Everest, because it was still the tallest but not yet discovered, then can you at least warn us if it's a trick question
Edit: That's my answer btw -- Mount Everest, incase you didn't catch the last part.