Harry learned another story about the mines in Heilbronn and Kochendorf. The lower levels of the mine, Harry knew, had been used as factories. The sixty-foot-wide by forty-foot-high chambers had been lined with concrete floors and electric lines to power the machinery. In the Kochendorf mine, one or more chambers had been designed as secret manufacturing centers for the mass production of a crucial Nazi invention: the jet engine. If the Nazis could have gotten the factory at Heilbronn running—they were supposedly just weeks away when the Americans arrived—it might have radically changed the
