The world's 'tallest' mountain might not be Everest

1Mount Everest, at 8,849 metres above sea level, is the world's 'highest' mountain. But 'tallest' can have three answers, depending on where you measure from.

2Measured from base to peak, the winner is Mauna Kea in Hawaii: more than half the volcano hides beneath the sea, rising over 10,000 metres from the ocean floor, with only about 4,200 metres above water. Measured by distance from Earth's centre, the winner is Chimborazo in Ecuador: Earth's spin makes the planet bulge at the equator, so although Chimborazo stands only about 6,260 metres above sea level, its summit is the point on Earth's surface farthest from the centre.

3So: highest above sea level — Everest; tallest base to peak — Mauna Kea; farthest from Earth's centre — Chimborazo. Change the definition, change the record — which is exactly what makes science fun.