One quibble. At the end it mentions why Mexico's west was of interest to the Spanish, but neglects possibly the most important part - it was where the Spanish galleons from the Philippines first landed after the grueling trip across the Pacific as detailed beautifully in Neal Stephenson's "Baroque Cycle".
Samurai were documented as guards on galleons brought to Mexico. It needs to be a movie.
https://en.m.wikipedia.org/wiki/Tai-Pan_(novel)
Shogun is about Japan in the Samurai period and Taipan is about Hong Kong a few centuries ago.
Both novels are about those periods and about Westerners interacting with those countries at that time.
https://en.m.wikipedia.org/wiki/James_Clavell
[
Clavell wanted to write a second novel because "that separates the men from the boys".[21] The money from King Rat enabled him to spend two years researching and then writing what became Tai-Pan (1966). It was a huge best-seller, and Clavell sold the film rights for a sizeable amount (although the film would not be made until 1986).[22]
]
Gradual elevation is certainly easier to build roads across than a cliff, and might be another reason there's less east-west divide in North America.
> Chile is so long because of the Andes. Here's a map of elevation in South America.
> You can't easily pass these mountains, and the tiny sliver of land to their west is Chile.
And going north<->south is so easy, that anyone doing it could likely cover the whole country pretty quick. So odds are, if there were two countries in that area, there would be just one pretty quickly.
Definitely one of those ‘geography defines the culture and the borders’ situations.