bridge into akiyoshi cave, yamaguchi

adventure akiyoshi akiyoshidai akiyoshido akiyoshidou ancient architectural asia august bridge brook cave cavern connects covered creek destination earth element entrance forest green historic honshu iconic ina inagawa inakawa japan japans karst largest limestone magical mine monument mystic natural nature park quasinational river rivulet rock scenic solutional special stone stream summer surrounding this time tourist underground view water yamaguchi