Aerial View of the Century of Progress International Exposition, Chicago, Illinois, 1934

Chicago's 1933-34 Century of Progress Exposition used the theme of progress to buoy national optimism during the darkest years of the Great Depression. The fairgrounds, shown here along the Lake Michigan shoreline, boasted many exhibition buildings and attractions. The tallest structure visible here is Havoline Motor Oil's fair building -- a twenty-one story, working thermometer.