Eratosthenes (3rd) calculated the circumference at 39,375 kilometers. Modern science estimates 40,000 kilometers.
Christianity was reluctant to recognize this truth but most scientists of the Middle Ages supported it. There are people today who believe the Earth is flat.
But it is not round. Centrifugal forces flatten the Earth at the poles. The polar diameter is 42 km less than the equatorial diameter.
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