This primary source comes from the Records of the National Park Service.
National Archives Identifier:
519941Full Citation: Close-up, 'Cliff Palace, Mesa Verde National Park,' Colorado. (Vertical Orientation); 1933-1942; Records of the National Park Service, Record Group 79. [Online Version, https://www.docsteach.org/documents/document/closeup-cliff-palace-mesa-verde-national-park-colorado-vertical-orientation, May 11, 2024]