What costs less, laying and operating cable underwater or over mountains? That is, what are the relative costs of land and submarine cables for long distances?<p>Looking at the runs that follow the coasts of South America, SE Asia, and northern Canada, I wonder why some of them weren't run over land. (Obviously very many cables do run over land; this map only shows submarine cables.)<p>In my imagination, it seems easier to drop a cable from big spool on a ship than to run it over mountains, for example, but I really have no idea.