Everest vs Mauna Loa

Weird thing I learned today? While Everest is usually first on the list when you ask people to list the "tallest mountain", that's actually--technically--not true.

Mauna Loa is the tallest mountain. Measured from the base of the mountain (which starts on the sea floor), Mauna Loa towers over Everest by about 3/4 of a mile -- at about 30,080 ft. Of course, about 15,000 of that is under water, but the mountain rises as a single slope from the sea bottom to its crown.

A technicality, to be sure, but at least one other site notes that

Geophysical evidence indicates that the full height of Mauna Loa above its base is an astounding 19 kilometers, more than twice the height of Mount Everest above sea level.