The ancient Inca citadel of Macchu Picchu is one of the new Seven Wonders of the World, but still to this day, no one knows what it was for or why it was abandoned. Do Athena and Tiernan have the theory that unlocks the mysteries to this mystical place high in the Andes? Or just a lot of jokes about sneezing? It's up to you, our Chief Detectives, to decide!