Between 1883 and 1893 Bosse traced the Mississippi from St. Paul, Minnesota, to St. Louis, Missouri. He worked as a mapmaker and photographer for the US Army Corps of Engineers (USACE). In close to 350 preserved photographs we can see how the USACE transformed the river into a commercial highway. Bosse used the curious cyanotype printing process, which is notable for its crisp, vivid blue tones.