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

I just thought i would through this out: Machu Picchu is not ancient, merely exotic and old (from our perspective). It was merely built 600 years ago.

It seems incredible, but is actually fairly modern.