National Geographic May 1916

Further Explorations in the Land of the Incas by the National Geographic Society { Further Explorations in the Land of the Incas: The Peruvian Expedition of 1915 of the National Geographic Society and Yale University}
Following up on his previous three groundbreaking visits to Machu Picchu, where he uncovered the long- forgotten Inca city, Hiram Bingham describes his 1915 expedition.
Staircase Farms of the Ancients: Astounding Farming Skill of Ancient Peruvians, Who Were Among the Most Industrious and Highly Organized People in History
Peruvians developed the most specialized agriculture in the Western Hemisphere centuries before Columbus reached America. The author examines how these people supported large populations in places where modern farmers would be helpless.