Machu Picchu of Peru

Although the archaeological discovery of Machu Picchu came nearly a hundred years ago, historians are still unsure of the function of this ancient Inca citadel.

The Inca had no system of writing and left no written records, and archaeologists have been left to piece together bits of evidence as to why Machu Picchu was built, what purpose it served, and why it was so quickly vacated.