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

You could well ask the same about Detroit.

Economic factors and changes in natural resources mean that a location no longer has the appeal it once did, so citizens move away.

Once that happens you have fewer and fewer people supporting a large infrastructure, which puts more strain on the city. At that point you either watch the inevitable decline or you find some new reason for people to stay.