In 1911, Hiram Bingham, famed American explorer, stumbled across a remote Inca city atop a high peak in the Andes. The site was called Machu Picchu – perhaps the most famous ruin in the world. What was its purpose? Was it, like Bingham believed, a military fortress? Or did this glorious ruin have a secret purpose? From the mountains of Peru, Josh will follow in the footsteps of Hiram Bingham. He builds a log bridge across a raging river, examines the stonework at the site, and reviews ancient manuscripts to discover the ‘true’ purpose of Machu Picchu.