You may have heard that Mount Everest is the world’s tallest mountain at 29,035 feet. Well, Hawaii says, “Everest, schmeverest!”

You would need a heck of a tape measure and some scuba gear, but if you could measure the Big Island’s Mauna Kea from its base on the sea floor all the way up to the summit, you’d find that Mauna Kea is 33,496 feet tall. It soars to the elevation of 13,796 feet above sea level, but there’s almost another 19,700 feet of this volcano that’s under water.

Even Maui’s Haleakala is taller than Mount Everest by about about 675 feet when you consider that there’s 19,680 feet of the volcano hidden under the ocean, and 10,023 feet above sea level.

Unlike the challenge of climbing the top of Mount Everest, reaching the summits of Mauna Kea and Haleakala are much easier. To get to the top of Mauna Kea on the Big Island, I recommend taking an organized tour. Read my advice for Mauna Kea sunset and stargazing tours. On Maui’s Haleakala, you can take an organized tour if you don’t want to drive, but I prefer driving up there before sunset for stargazing and watching the sun rise above the clouds and over a crater. See my tips for visiting Haleakala for sunrise.