If any visitor passes in between the Swallow Grotto to the Tzumu Bridge, all they must do is crane their heads upward and gaze at the cliffs to know how difficult it was to carve a road out of this terrain as slick as glass.
如果遊客行經燕子口到慈母橋之間，只要抬頭上望峭壁，就可知道若要在如同玻璃一般光滑堅硬的地形上，鑿出一通路，是多麼困難的事。