Question: For which war was the ammunition plant, located in Illinois, and now a tallgrass prairie reserve; the largest conservation site in the Chicago Wilderness region, originally opened?
Sentence (from "Joliet Army Ammunition Plant"): Joliet Army Ammunition Plant (JOAAP, formerly known as the Joliet Arsenal) was a United States Army arsenal located in Will County, Illinois, near Elwood, Illinois, south of Joliet, Illinois.
Relevant evidence: Yes