What is Machu Picchu? There is no reference to Machu Picchu in Inca literature or folklore, so what is this culturally sophisticated engineering city in the Andes of Peru? Many archeologists believe that it was constructed as a retreat for the Inca nobility between 1400 and 1500 AD. But the extensive terracing suggests it may have been a center for crop testing or used as a trading hub. Who lived …