World Subways, Presented By Scale
Check it out... it's very cool and lets you get a better feel for city size.
Subway systems of the world, presented on the same scale.
(And on a total aside, sometimes I come across content in the strangest way.
I work at a bookstore. I use LibraryThing, both professionally and personally. So I read their development blog. Well, LibraryThingforLibraries is finally in a library. So I go over to the personal blog of the person who instituted it in the 1st library. And I came across the above gem.)