In North America, the lines that matter most on the map are not the US-Canada border or the US-Mexico border, but the dense network of roads and railways and pipelines and electricity grids and even water canals that are forming an integrated North American union.
在北美，地图上意义最重大的一条线 并不是美加边境或者美墨边境， 而是公路、铁路、管道的交织网络， 还有电力网络，甚至是运河系统， 一个和谐的北美联盟因这些而形成。