Why was Machu Picchu not destroyed?

Related questions

1. Is Lima Peru dangerous?
2. Is Peru safe?
3. Why did Machu Picchu take so long?
4. Can you do the Inca Trail without a guide?
5. Is Machu Picchu closing to the public?
6. Why is Machu Picchu one of the 7 Wonders of the World?
7. Where should I stay when visiting Machu Picchu?
8. Is there Uber in Peru?
9. What is the cheapest way to get from Cusco to Machu Picchu?
10. What is Machu Picchu famous for?

Tags

1. #great
2. #roads
3. #reason
4. #after
5. #generally
6. #picchu
7. #ancient
8. #center
9. #historians
10. #aristocracy
11. #spanish
12. #destroyed
13. #conquest
14. #unknown
15. #conquerors
16. #still
17. #remains
18. #agricultural
19. #important
20. #agree
21. #housing
22. #machu