“In the mid-20th century we began launching satellites into space that would help us determine the exact circumference of the Earth: 40,030 km. But over 2000 years earlier, a man in Ancient Greece came up with nearly the exact same figure using just a stick and his brain.”
Eratosthenes is often referred to as the “father of geography” for creating meridians and parallels on his maps to organize global information, classifying climatic zones, and as shown in the video, calculating the circumference of the Earth. Plus, he coined the terms so he gets the credit. If you have never pondered the meaning of the word “geometry,” the accomplishments of Eratosthenes will certainly show that the mathematical prowess was at the heart of expanding our collective geographic knowledge (additionally, here is a retro Carl Sagan in a video clip from Cosmos that inspired this clip).