Polish Constitution Day Parade in Chicago’s Loop, May 2, 2015. The banner reads, in English, “Two homelands, one heart,” expressing the dual nature of Polonia. (Photograph by Dominic Pacyga)

Local historian Dominic Pacyga tells us about his new book “American Warsaw: The Rise, Fall, and Rebirth of Polish Chicago.”

They closed some 44 years ago, but Chicago's Union Stockyards profoundly shaped the development of the city and the modern world. Dominic Pacyga, a local historian and former stockyard worker, tells the story in his new book "Slaughterhouse.” Pacyga joins us tonight.