This is more complicated than you'll want (unless there are labor history bluffs among you) but I mention it for future readers of this thread: The Labor Trail, a very detailed list, map and description of Chicago sites important to US and local labor history. There's much more than Haymarket Square and the Pullman neighborhood!

The home page for the effort is http://www.labortrail.org/index.html, and there's a lovely interactive map on the site. A hard-copy map can be ordered from http://www.labortrail.org/lt-00-order.html.

Even if you are not headed for Chicago, the map and site are excellent educational tools, recognizing its fundamental pro-collective-bargaining stance.