Diane Waggoner, curator of nineteenth-century photographs, National Gallery of Art. The first exhibition to focus exclusively on photographs made in the eastern half of the United States during the 19th century, East of the Mississippi: Nineteenth-Century American Landscape Photography showcases some 175 works—from daguerreotypes and stereographs to albumen prints and cyanotypes—as well as several photographers whose efforts have often gone unheralded. Celebrating natural wonders such as Niagara Falls and the White Mountains, as well as capturing a cultural landscape fundamentally altered by industrialization, the Civil War, and tourism, these photographs not only helped shape America’s national identity but also played a role in the emergence of environmentalism. Diane Waggoner introduces the exhibition in this opening-day lecture recorded on March 12, 2017, at the National Gallery of Art. East of the Mississippi is on view through July 16, 2017.