underwater rain on the thousand rice fields

adventure akiyoshi akiyoshido akiyoshidou ancient asia cave cavern chimachida dam dark destination dripping drips dripstone earth factory fall fields flowstone formation geology historic honshu inside japan japans karst kasazukushi largest limestone mine mineral monument mystic natural nature park prefecture rice rimstone rock scenic science solutional special speleology speleothem stalactite still stone this thousand time tourist umbrella underground view water yamaguchi