When was the first defensive wall built?

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Tags

1. #group
2. #constructed
3. #fortified
4. #rulers
5. #sumerian
6. #world
7. #defensive
8. #known
9. #barrier
10. #incursions
11. #earliest
12. #shulgi
13. #first
14. #build
15. #civilization
16. #nomadic
17. #ancient
18. #making
19. #amorites
20. #mesopotamia
21. #century
22. #tribesmen
23. #massive
24. #during