Started an argument with my much smarter wife because she said North and South America are not two separate continents. She was right, because continents are only defined by convention.
Iirc its actually based on some guy assuming a river was a cannal and using it as a geographical border and no one really checking until the border had stuck.
I remember always questioning that one as a kid. The answer I always got was something about mountains. For some reason, I think the true history, like a lot of arbitrary divisions is probably ✨racism✨