Three Chacoan great houses—Pueblo del Arroyo, Pueblo Bonito, and Chetro Ketl—are visible in this photograph from 1929. The light, cross-shaped feature is an ancient gridded field system. Historic structures can be seen near Pueblo del Arroyo and Pueblo Bonito, and active excavation was taking place at Chetro Ketl. Photograph by Charles A. and Anne Morrow Lindbergh, 1929.