A hundred feet above the Apurimac River, near the remote village of Huinchiri, Peru there is a suspension bridge that connects the Limi-Cuzzo Road. It has been there since the 14th century. Using four miles of braided coya grass, the Inca constructed the bridge in phases. First a bowman attached a fine thread to an arrow and fired it across the gorge. A man on the other side tied a cord to the thread and fired it back across the gorge. The cord was then pulled across. One by one the Inca added thicker and thicker ropes,…