For those of you who don’t know who Eratosthenes was, he supposedly proved flat-earth wrong in 240 B.C.E using a mathematical standpoint. *Eratosthenes erected a pole in Alexandria, and on the summer solstice he observed that it cast a shadow, proving that the Sun was not directly overhead but slightly south. Recognizing the curvature of the Earth and knowing the distance between the two cities enabled Eratosthenes to calculate the planet's circumference.*
