Anybody who knows about Pittsburgh politics knows about the division between voters in the East End of the city and those elsewhere. You can't get a better illustration than the one above from the University Center for Social & Urban Research on those voting in favor of the city library tax. (Click pic for bigger version.)
The page is also a worth a visit for the usual map showing the surge of Democratic votes in the city and Mon Valley, versus the major pockets of red in the North Hills.
Graphic: University Center for Social & Urban Research/Pittsburgh Urban Blog