Quiz: Can you name these cities just by looking at their subway maps?

I really don't know what to tell you if you get this one wrong. Which city's transit map is this? Washington, DC - Atlanta, GA - Pawtucket, RI - Benghazi
"Okay. You guys had a blast with last week's street grid quiz, so how about a variation on that theme? This time I've taken the official subway/train/metro system maps of 10 cities and stripped them of all identifying information. These maps include metropolitan rail transit only -- no bus lines, no roads and no Amtrak. These should be a little harder to identify than last week's maps -- rather than a dense network of roads all you get is a stylized skeleton of a region's transit system. But you do have one thing going for you this time: there's no commuter rail in Benghazi."
Washington Post