eli5: Why were some ancient cities like Palmyra and Machu Picchu left to ruin and fall apart over hundreds of years instead of being repopulated?

Question

eli5: Why were some ancient cities like Palmyra and Machu Picchu left to ruin and fall apart over hundreds of years instead of being repopulated?

In: 1677

Answer 1

It’s normally because the conditions that led to that place being attractive to settle changing. For instance in the Fertile Crescent, the rivers that initially made the region so fertile made the land so salty that nothing would grow. Watch The Fall of Civilizations on YouTube.