National Geographic : 1942 Aug
Peru on Parade ~ NiaIonai ueograpnlc Boclery r'inlay uy Ilenry -ilayuipson Pre-Inca Indians Cut and Placed the Mighty Stones of Sacsahuaman This monumental fortress, on the heights above Cuzco, is one of the most amazing works of ancient man in the Western Hemisphere. Some of the huge stones measure 15 to 20 feet in height and weigh many tons. No mortar or cement was used. The boulders were shaped and fitted so accurately that a knife blade can not be thrust between them. The builders knew not the use of iron; stone tools, fiber ropes, and primitive mechanical devices erected this wall.