Map of transatlantic submarine cable lines as of 2014, courtesy of SubmarineCableMap.com.

I think looking at the map on the right shows how stratified the layout of communication technology is for the Atlantic Ocean region. So much up top and spilling vertically down (on both sides), but so little between the bottom.

Why are there so few submarine cables between Africa and South America? Between Nigeria/South Africa/Angola and Brazil/Argentina/Venezuela?

Surely there would be lots of historical links to share between the two continents, such as post-colonial, post-slavery histories? Or especially the large portion of slaves from West Africa heading to the Portuguese colony of Brazil? Or the histories of exploitation of labor and natural resources? Or musical and artistic commonalities?

I mean, Brazil literally faces several African countries along the same set of latitudinal lines (more so than a good portion of North America faces Europe), but yet there are…