Why do people know these prefectures?

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Across
  1. 7. famous for Mt. Fuji
  2. 9. known for Crayon Shin-chan
  3. 11. known for its sand dunes
  4. 12. famous for its hot springs
  5. 15. famous for ninjas
  6. 17. famous for its whirlpools
  7. 19. famous for its hot springs
  8. 20. famous for its apples
  9. 21. known for having lots of snow
  10. 22. known for its cherries
  11. 23. famous for Kumamon
Down
  1. 1. famous for Mt. Fuji
  2. 2. famous for its wisteria
  3. 3. known for dinosaurs
  4. 4. famous for Dejima
  5. 5. famous for its udon
  6. 6. famous for its volcano
  7. 8. known for its Atomic Dome
  8. 10. famous for its kanto festival
  9. 13. known for its nuclear fallout
  10. 14. known for its snow monkeys
  11. 15. famous for its tanabata festival
  12. 16. known for their ramen
  13. 18. famous for its beaches