Why is Mecca the holy city of Islam?

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Tags

1. #birthplace
2. #specifically
3. #obligatory
4. #muhammad
5. #revelation
6. #ammad
7. #first
8. #pilgrimage
9. #known
10. #islam
11. #regarded
12. #quran
13. #mecca
14. #religion
15. #holiest
16. #muslims