Machu Picchu in Peru – the famous lost city of the Incas. Archaeologists discovered this mountaintop city one hundred years ago, but its purpose remains a hotly debated mystery. Was it a religious observatory or a holiday retreat for the emperor?

Could religious carvings and gruesomely deformed skeletons found in the city hold a crucial clue as to why this city was built? A newly uncovered network of roads places Machu Picchu as a strategic outpost for the Inca Emperor Pachacuti, but mysterious rock art suggests the site’s origins may be far older.

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