Why is the Mona Lisa so valuable?

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Tags

1. #where
2. #expression
3. #achieved
4. #livingstone
5. #filter
6. #vinci
7. #smiling
8. #unusual
9. #painting
10. #cheerfully
11. #homing
12. #detail
13. #depending
14. #looked
15. #demure
16. #effect
17. #smile
18. #blurred
19. #changes