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

Peruvian here, Macchu picchu was a ceremonial city for the Incas. Due to the complex access to it (jungle between Spanish and place) seems like it was never found. However local people knew about it. In 1912 Hiram Brigham discovered this and started to study the place.

Macchu picchu is not the only city, there are another ones that needs to be studied like Kuelap or even discovered. Lack of budget, access and data are why are not being discovered yet.