Just for the heck of it, Randall Munroe, mastermind behind the geek-favorite webcomic XKCD, has created a map showing all of North-America's subways connected, from Canada to Mexico. The text's overlay includes this interesting bit of trivia: "About one in three North American subway stops are in NYC."
As usual with XKCD maps, there's all kinds of funny details hidden all around. See if you can find Springfield's monorail!
You can see an extra-large version of the map here.
Note: I've used the slideshow template to get a larger image. There's no second slide.
See also: The 2014 Mercedes B-Class Electric Drive is coming to the U.S.