G32

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Across
  1. 5. Underground chamber
  2. 6. Ground collapse area
  3. 11. Region near the equator
  4. 12. Half of the Earth
  5. 14. Large cave
  6. 15. Variation in land height
  7. 16. Underground water layer
  8. 17. Ridge separating watersheds
  9. 19. Southern polar region
  10. 20. Distance east or west of prime meridian
Down
  1. 1. Limestone landscape
  2. 2. Land draining into a river
  3. 3. Man-made water shaft
  4. 4. Ozone-containing layer
  5. 7. Natural groundwater flow
  6. 8. Flat-topped hill
  7. 9. Zero-degree latitude line
  8. 10. Distance north or south of equator
  9. 13. Height above sea level
  10. 18. Northern polar region