Contrary to popular belief, the answer is Ecuador, as the Earth isn’t a perfect sphere. As the Earth is constantly spinning, centrifugal force causes it to bulge out at the equator much like a water balloon would if you placed it on a table and pressed on the top.

Let’s look at Mount Chimborazo in Ecuador. The summit of Chimborazo is 6,267 m (20,561 ft) above sea level, which is quite large but not quite the highest mountain in the Andes. If you take into account the Earth’s equatorial bulge, a straight line from the summit down to the estimated centre of our planet would be 6,384.4 km (3,967.1 mi).

Now look at Mount Everest, widely known as the tallest mountain in the world. The summit of Everest is 8,848 m (29,029 ft) above sea level, but a straight line from the summit to the centre of the Earth would only be 6,382.3 km (3,965.8 mi).

So even though the summit of Chimborazo is about 2,400 m closer to sea level than Everest, it’s still 2,100 m further away from the centre of the Earth! By this logic, three more mountains (Huascaran, Cotopaxi and Kilimanjaro) around the world are actually “higher” than Everest as well.

Sadly our newly defined rules aren’t taken into account when deciding on the world’s highest mountain, so although Chimborazo is ranked the highest in distance from the centre of the Earth, Mount Everest still wins since we always measure to sea level.

If you’re a climber and neither one these appeals, you could always try Gangkhar Puensum in Bhutan. It’s considered the highest unclimbed mountain in the world1.