The size of the big blue ball

The Earth's equatorial circumference (40,075 km) is greater than its polar circumference (40,008 km) by 67 km.

So as you can see our big blue ball is slightly bulged at the middle due to the effects of the Earth's rotation.

This means that contrary to popular opinion the highest point on Earth (if you take Earth's centre as the start point rather than sea level) isn’t Mt Everest it is in fact Mt Chimborazo in Ecuador.

A mountain that hardly anyone has heard of.