Guns,Germs, and Steel (1997) Jared Diamond

Jared Diamond: Here were Europe and Asia forming the continent of Eurasia, a giant continent but it’s stretched out from east to west, and narrows from north to south. The American continent is long from north to south, narrow from east to west – very narrow at Panama where it narrows down to less than 100 miles. The two continents are of the same lengths, about 8,000 miles in maximum dimensions, but Eurasia is 8,000 miles from east to west, and the Americas are 8,000 miles from north to south, it’s as if these continents were rotated 90 degrees of each other.