Mount Everest isn't Earth's highest point; scientists say another mountain beats it

As a kid, you were told that Mount Everest is the tallest mountain on Earth. It’s in every textbook, every geography lesson, every trivia night. But here's the thing: it all depends on what you mean by “tallest,” and if you change the definition, the whole narrative flips over.

The mountain that beats Everest, by a long mile
Mount Chimborazo is a dormant volcano in Ecuador that most people have never heard of. It doesn't even compare with Everest's 29,029 feet, at 20,564 feet above sea level. Everest wins hands down, using the old-fashioned measurement height above sea level.

But here’s where it gets interesting. Measured from the center of the Earth outwards, Chimborazo wins, hands down. But, according to NOAA's National Ocean Service, while Chimborazo is thousands of feet shorter above sea level, its peak is more than 6,800 feet farther from Earth's center than Everest's peak. That makes Chimborazo the closest place on Earth to the stars.

Why Earth's shape changes everything
This is no trick of math. It all boils down to the actual shape of our planet. The Earth is not a perfect sphere. Our planet rotates constantly, generating a centrifugal force that makes it bulge at the equator in terms of its diameter. Scientists call this shape an oblate spheroid, basically a sphere that's been pinched at the poles and puffed out in the middle.

Earth is about 43 kilometers (27 miles) wider around the equator than it is around the poles. That difference sounds small on a planetary scale, but it's huge when you're comparing mountain peaks.

Chimborazo sits only one degree south of the equator right on that bulge. Mount Everest is in the Himalayas, roughly a third of the way to the North Pole, where the surface of the Earth curves inwards. So while Everest is much taller above sea level, it’s starting from a lower baseline. Chimborazo has a huge advantage by being in the right place.

And Everest isn't even the tallest, by another measure
If you measure a mountain from base to peak, not sea level to peak, Everest doesn't win that one either.

The award goes to Mauna Kea, a volcano on Hawaii's Big Island. Most of it is underwater. Mauna Kea rises more than 33,500 feet from its base on the ocean floor to its summit, more than 4,000 feet higher than Everest. You can't see most of it, though, because the Pacific Ocean is sitting on top of it.

Three mountains, three different versions of the “tallest”
So which mountain is really the tallest? It depends on the question you ask.

If you mean highest above sea level, which is the usual standard in geography and mountaineering, Everest wins. The winner for the summit farthest from the center of the Earth and consequently closest to outer space is Chimborazo. And if you want the mountain with the greatest total height from base to peak, Mauna Kea is your answer.

None of these answers is wrong. They simply answer different questions.

Why this is more important than you think
To most Americans, Everest is “the top of the world.” And for climbers, it still is; the conditions, the altitude, and the effort needed to summit Everest are in a whole different league. Climbing Chimborazo takes about two weeks. Everest requires almost two months of grueling preparation and acclimatization.

But the Chimborazo story is a good reminder that facts we learned in grade school sometimes come with a caveat. The shape of the planet itself can subtly affect the answer, and it turns out that the geography of the world is far more complicated and more interesting than any one headline can capture.